Adding upstream version 16.2.11+ds.upstream/16.2.11+dsupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

19 files changed, 9148 insertions, 0 deletions

diff --git a/src/c-ares/m4/.gitignore b/src/c-ares/m4/.gitignore
new file mode 100644
index 000000000..f0f1d4db9
--- /dev/null
+++ b/src/c-ares/m4/.gitignore
@@ -0,0 +1,6 @@
+libtool.m4
+libtool.m4.tmp
+ltoptions.m4
+ltsugar.m4
+ltversion.m4
+lt~obsolete.m4
diff --git a/src/c-ares/m4/ax_check_user_namespace.m4 b/src/c-ares/m4/ax_check_user_namespace.m4
new file mode 100644
index 000000000..27ba69821
--- /dev/null
+++ b/src/c-ares/m4/ax_check_user_namespace.m4
@@ -0,0 +1,54 @@
+# -*- Autoconf -*-
+
+# SYNOPSIS
+#
+#   AX_CHECK_USER_NAMESPACE
+#
+# DESCRIPTION
+#
+#   This macro checks whether the local system supports Linux user namespaces.
+#   If so, it calls AC_DEFINE(HAVE_USER_NAMESPACE).
+
+AC_DEFUN([AX_CHECK_USER_NAMESPACE],[dnl
+ AC_CACHE_CHECK([whether user namespaces are supported],
+  ax_cv_user_namespace,[
+  AC_LANG_PUSH([C])
+  AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#define _GNU_SOURCE
+#include <fcntl.h>
+#include <sched.h>
+#include <signal.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+int userfn(void *d) {
+  usleep(100000);  /* synchronize by sleep */
+  return (getuid() != 0);
+}
+char userst[1024*1024];
+int main() {
+  char buffer[1024];
+  int rc, status, fd;
+  pid_t child = clone(userfn, userst + 1024*1024, CLONE_NEWUSER|SIGCHLD, 0);
+  if (child < 0) return 1;
+
+  sprintf(buffer, "/proc/%d/uid_map", child);
+  fd = open(buffer, O_CREAT|O_WRONLY|O_TRUNC, 0755);
+  sprintf(buffer, "0 %d 1\n", getuid());
+  write(fd, buffer, strlen(buffer));
+  close(fd);
+
+  rc = waitpid(child, &status, 0);
+  if (rc <= 0) return 1;
+  if (!WIFEXITED(status)) return 1;
+  return WEXITSTATUS(status);
+}
+  ]])],[ax_cv_user_namespace=yes],[ax_cv_user_namespace=no],[ax_cv_user_namespace=no])
+ AC_LANG_POP([C])
+ ])
+ if test "$ax_cv_user_namespace" = yes; then
+   AC_DEFINE([HAVE_USER_NAMESPACE],[1],[Whether user namespaces are available])
+ fi
+]) # AX_CHECK_USER_NAMESPACE
diff --git a/src/c-ares/m4/ax_check_uts_namespace.m4 b/src/c-ares/m4/ax_check_uts_namespace.m4
new file mode 100644
index 000000000..cf7b145c3
--- /dev/null
+++ b/src/c-ares/m4/ax_check_uts_namespace.m4
@@ -0,0 +1,76 @@
+# -*- Autoconf -*-
+
+# SYNOPSIS
+#
+#   AX_CHECK_UTS_NAMESPACE
+#
+# DESCRIPTION
+#
+#   This macro checks whether the local system supports Linux UTS namespaces.
+#   Also requires user namespaces to be available, so that non-root users
+#   can enter the namespace.
+#   If so, it calls AC_DEFINE(HAVE_UTS_NAMESPACE).
+
+AC_DEFUN([AX_CHECK_UTS_NAMESPACE],[dnl
+ AC_CACHE_CHECK([whether UTS namespaces are supported],
+  ax_cv_uts_namespace,[
+  AC_LANG_PUSH([C])
+  AC_RUN_IFELSE([AC_LANG_SOURCE([[
+#define _GNU_SOURCE
+#include <sched.h>
+#include <signal.h>
+#include <stdio.h>
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+int utsfn(void *d) {
+  char buffer[1024];
+  const char *name = "autoconftest";
+  int rc = sethostname(name, strlen(name));
+  if (rc != 0) return 1;
+  gethostname(buffer, 1024);
+  return (strcmp(buffer, name) != 0);
+}
+
+char st2[1024*1024];
+int fn(void *d) {
+  pid_t child;
+  int rc, status;
+  usleep(100000);  /* synchronize by sleep */
+  if (getuid() != 0) return 1;
+  child = clone(utsfn, st2 + 1024*1024, CLONE_NEWUTS|SIGCHLD, 0);
+  if (child < 0) return 1;
+  rc = waitpid(child, &status, 0);
+  if (rc <= 0) return 1;
+  if (!WIFEXITED(status)) return 1;
+  return WEXITSTATUS(status);
+}
+char st[1024*1024];
+int main() {
+  char buffer[1024];
+  int rc, status, fd;
+  pid_t child = clone(fn, st + 1024*1024, CLONE_NEWUSER|SIGCHLD, 0);
+  if (child < 0) return 1;
+
+  sprintf(buffer, "/proc/%d/uid_map", child);
+  fd = open(buffer, O_CREAT|O_WRONLY|O_TRUNC, 0755);
+  sprintf(buffer, "0 %d 1\n", getuid());
+  write(fd, buffer, strlen(buffer));
+  close(fd);
+
+  rc = waitpid(child, &status, 0);
+  if (rc <= 0) return 1;
+  if (!WIFEXITED(status)) return 1;
+  return WEXITSTATUS(status);
+}
+]])
+  ],[ax_cv_uts_namespace=yes],[ax_cv_uts_namespace=no],[ax_cv_uts_namespace=no])
+ AC_LANG_POP([C])
+ ])
+ if test "$ax_cv_uts_namespace" = yes; then
+   AC_DEFINE([HAVE_UTS_NAMESPACE],[1],[Whether UTS namespaces are available])
+ fi
+]) # AX_CHECK_UTS_NAMESPACE
diff --git a/src/c-ares/m4/ax_code_coverage.m4 b/src/c-ares/m4/ax_code_coverage.m4
new file mode 100644
index 000000000..5120c3bb1
--- /dev/null
+++ b/src/c-ares/m4/ax_code_coverage.m4
@@ -0,0 +1,219 @@
+# ===========================================================================
+#     http://www.gnu.org/software/autoconf-archive/ax_code_coverage.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_CODE_COVERAGE()
+#
+# DESCRIPTION
+#
+#   Defines CODE_COVERAGE_CFLAGS and CODE_COVERAGE_LDFLAGS which should be
+#   included in the CFLAGS and LIBS/LDFLAGS variables of every build target
+#   (program or library) which should be built with code coverage support.
+#   Also defines CODE_COVERAGE_RULES which should be substituted in your
+#   Makefile; and $enable_code_coverage which can be used in subsequent
+#   configure output. CODE_COVERAGE_ENABLED is defined and substituted, and
+#   corresponds to the value of the --enable-code-coverage option, which
+#   defaults to being disabled.
+#
+#   Test also for gcov program and create GCOV variable that could be
+#   substituted.
+#
+#   Note that all optimisation flags in CFLAGS must be disabled when code
+#   coverage is enabled.
+#
+#   Usage example:
+#
+#   configure.ac:
+#
+#     AX_CODE_COVERAGE
+#
+#   Makefile.am:
+#
+#     @CODE_COVERAGE_RULES@
+#     my_program_LIBS = ... $(CODE_COVERAGE_LDFLAGS) ...
+#     my_program_CFLAGS = ... $(CODE_COVERAGE_CFLAGS) ...
+#
+#   This results in a "check-code-coverage" rule being added to any
+#   Makefile.am which includes "@CODE_COVERAGE_RULES@" (assuming the module
+#   has been configured with --enable-code-coverage). Running `make
+#   check-code-coverage` in that directory will run the module's test suite
+#   (`make check`) and build a code coverage report detailing the code which
+#   was touched, then print the URI for the report.
+#
+#   This code was derived from Makefile.decl in GLib, originally licenced
+#   under LGPLv2.1+.
+#
+# LICENSE
+#
+#   Copyright (c) 2012 Philip Withnall
+#   Copyright (c) 2012 Xan Lopez
+#   Copyright (c) 2012 Christian Persch
+#   Copyright (c) 2012 Paolo Borelli
+#   Copyright (c) 2012 Dan Winship
+#   Copyright (c) 2015 Bastien ROUCARIES
+#
+#   This library is free software; you can redistribute it and/or modify it
+#   under the terms of the GNU Lesser General Public License as published by
+#   the Free Software Foundation; either version 2.1 of the License, or (at
+#   your option) any later version.
+#
+#   This library is distributed in the hope that it will be useful, but
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
+#   General Public License for more details.
+#
+#   You should have received a copy of the GNU Lesser General Public License
+#   along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+#serial 5
+
+AC_DEFUN([AX_CODE_COVERAGE],[
+	dnl Check for --enable-code-coverage
+	AC_REQUIRE([AC_PROG_SED])
+
+	# allow to override gcov location
+	AC_ARG_WITH([gcov],
+	  [AS_HELP_STRING([--with-gcov[=GCOV]], [use given GCOV for coverage (GCOV=gcov).])],
+	  [_AX_CODE_COVERAGE_GCOV_PROG_WITH=$with_gcov],
+	  [_AX_CODE_COVERAGE_GCOV_PROG_WITH=gcov])
+
+	AC_MSG_CHECKING([whether to build with code coverage support])
+	AC_ARG_ENABLE([code-coverage],
+	  AS_HELP_STRING([--enable-code-coverage],
+	  [Whether to enable code coverage support]),,
+	  enable_code_coverage=no)
+
+	AM_CONDITIONAL([CODE_COVERAGE_ENABLED], [test x$enable_code_coverage = xyes])
+	AC_SUBST([CODE_COVERAGE_ENABLED], [$enable_code_coverage])
+	AC_MSG_RESULT($enable_code_coverage)
+
+	AS_IF([ test "$enable_code_coverage" = "yes" ], [
+		# check for gcov
+		AC_CHECK_TOOL([GCOV],
+		  [$_AX_CODE_COVERAGE_GCOV_PROG_WITH],
+		  [:])
+		AS_IF([test "X$GCOV" = "X:"],
+		  [AC_MSG_ERROR([gcov is needed to do coverage])])
+		AC_SUBST([GCOV])
+
+		dnl Check if gcc is being used
+		AS_IF([ test "$GCC" = "no" ], [
+			AC_MSG_ERROR([not compiling with gcc, which is required for gcov code coverage])
+		])
+
+		# List of supported lcov versions.
+		lcov_version_list="1.6 1.7 1.8 1.9 1.10 1.11"
+
+		AC_CHECK_PROG([LCOV], [lcov], [lcov])
+		AC_CHECK_PROG([GENHTML], [genhtml], [genhtml])
+
+		AS_IF([ test "$LCOV" ], [
+			AC_CACHE_CHECK([for lcov version], ax_cv_lcov_version, [
+				ax_cv_lcov_version=invalid
+				lcov_version=`$LCOV -v 2>/dev/null | $SED -e 's/^.* //'`
+				for lcov_check_version in $lcov_version_list; do
+					if test "$lcov_version" = "$lcov_check_version"; then
+						ax_cv_lcov_version="$lcov_check_version (ok)"
+					fi
+				done
+			])
+		], [
+			lcov_msg="To enable code coverage reporting you must have one of the following lcov versions installed: $lcov_version_list"
+			AC_MSG_ERROR([$lcov_msg])
+		])
+
+		case $ax_cv_lcov_version in
+			""|invalid[)]
+				lcov_msg="You must have one of the following versions of lcov: $lcov_version_list (found: $lcov_version)."
+				AC_MSG_ERROR([$lcov_msg])
+				LCOV="exit 0;"
+			;;
+		esac
+
+		AS_IF([ test -z "$GENHTML" ], [
+			AC_MSG_ERROR([Could not find genhtml from the lcov package])
+		])
+
+		dnl Build the code coverage flags
+		CODE_COVERAGE_CFLAGS="-O0 -g -fprofile-arcs -ftest-coverage"
+		CODE_COVERAGE_LDFLAGS="-lgcov"
+
+		AC_SUBST([CODE_COVERAGE_CFLAGS])
+		AC_SUBST([CODE_COVERAGE_LDFLAGS])
+
+CODE_COVERAGE_RULES='
+# Code coverage
+#
+# Optional:
+#  - CODE_COVERAGE_DIRECTORY: Top-level directory for code coverage reporting.
+#    (Default: $(top_builddir))
+#  - CODE_COVERAGE_OUTPUT_FILE: Filename and path for the .info file generated
+#    by lcov for code coverage. (Default:
+#    $(PACKAGE_NAME)-$(PACKAGE_VERSION)-coverage.info)
+#  - CODE_COVERAGE_OUTPUT_DIRECTORY: Directory for generated code coverage
+#    reports to be created. (Default:
+#    $(PACKAGE_NAME)-$(PACKAGE_VERSION)-coverage)
+#  - CODE_COVERAGE_LCOV_OPTIONS_GCOVPATH: --gcov-tool pathtogcov
+#  - CODE_COVERAGE_LCOV_OPTIONS_DEFAULT: Extra options to pass to the lcov instance.
+#    (Default: $CODE_COVERAGE_LCOV_OPTIONS_GCOVPATH)
+#  - CODE_COVERAGE_LCOV_OPTIONS: Extra options to pass to the lcov instance.
+#    (Default: $CODE_COVERAGE_LCOV_OPTIONS_DEFAULT)
+#  - CODE_COVERAGE_GENHTML_OPTIONS: Extra options to pass to the genhtml
+#    instance. (Default: empty)
+#  - CODE_COVERAGE_IGNORE_PATTERN: Extra glob pattern of files to ignore
+#
+# The generated report will be titled using the $(PACKAGE_NAME) and
+# $(PACKAGE_VERSION). In order to add the current git hash to the title,
+# use the git-version-gen script, available online.
+
+# Optional variables
+CODE_COVERAGE_DIRECTORY ?= $(top_builddir)
+CODE_COVERAGE_OUTPUT_FILE ?= $(PACKAGE_NAME)-$(PACKAGE_VERSION)-coverage.info
+CODE_COVERAGE_OUTPUT_DIRECTORY ?= $(PACKAGE_NAME)-$(PACKAGE_VERSION)-coverage
+CODE_COVERAGE_LCOV_OPTIONS_GCOVPATH ?= --gcov-tool "$(GCOV)"
+CODE_COVERAGE_LCOV_OPTIONS_DEFAULT ?= $(CODE_COVERAGE_LCOV_OPTIONS_GCOVPATH)
+CODE_COVERAGE_LCOV_OPTIONS ?= $(CODE_COVERAGE_LCOV_OPTIONS_DEFAULT)
+CODE_COVERAGE_GENHTML_OPTIONS ?=
+CODE_COVERAGE_IGNORE_PATTERN ?=
+
+code_coverage_quiet = $(code_coverage_quiet_$(V))
+code_coverage_quiet_ =
+code_coverage_quiet_0 = --quiet
+
+# Use recursive makes in order to ignore errors during check
+check-code-coverage:
+	-$(MAKE) $(AM_MAKEFLAGS) -k check
+	$(MAKE) $(AM_MAKEFLAGS) code-coverage-capture
+
+# Capture code coverage data
+code-coverage-capture: code-coverage-capture-hook
+	$(LCOV) $(code_coverage_quiet) --directory $(CODE_COVERAGE_DIRECTORY) --capture --output-file "$(CODE_COVERAGE_OUTPUT_FILE).tmp" --test-name "$(PACKAGE_NAME)-$(PACKAGE_VERSION)" --no-checksum --compat-libtool $(CODE_COVERAGE_LCOV_OPTIONS)
+	$(LCOV) $(code_coverage_quiet) --directory $(CODE_COVERAGE_DIRECTORY) --remove "$(CODE_COVERAGE_OUTPUT_FILE).tmp" "/tmp/*" $(CODE_COVERAGE_IGNORE_PATTERN) --output-file "$(CODE_COVERAGE_OUTPUT_FILE)"
+	-@rm -f $(CODE_COVERAGE_OUTPUT_FILE).tmp
+	LANG=C $(GENHTML) $(code_coverage_quiet) --prefix $(CODE_COVERAGE_DIRECTORY) --output-directory "$(CODE_COVERAGE_OUTPUT_DIRECTORY)" --title "$(PACKAGE_NAME)-$(PACKAGE_VERSION) Code Coverage" --legend --show-details "$(CODE_COVERAGE_OUTPUT_FILE)" $(CODE_COVERAGE_GENHTML_OPTIONS)
+	@echo "file://$(abs_builddir)/$(CODE_COVERAGE_OUTPUT_DIRECTORY)/index.html"
+
+# Hook rule executed before code-coverage-capture, overridable by the user
+code-coverage-capture-hook:
+
+clean: code-coverage-clean
+code-coverage-clean:
+	-$(LCOV) --directory $(top_builddir) -z
+	-rm -rf $(CODE_COVERAGE_OUTPUT_FILE) $(CODE_COVERAGE_OUTPUT_FILE).tmp $(CODE_COVERAGE_OUTPUT_DIRECTORY)
+	-find . -name "*.gcda" -o -name "*.gcov" -delete
+
+GITIGNOREFILES ?=
+GITIGNOREFILES += $(CODE_COVERAGE_OUTPUT_FILE) $(CODE_COVERAGE_OUTPUT_DIRECTORY)
+
+DISTCHECK_CONFIGURE_FLAGS ?=
+DISTCHECK_CONFIGURE_FLAGS += --disable-code-coverage
+
+.PHONY: check-code-coverage code-coverage-capture code-coverage-capture-hook code-coverage-clean
+'
+	AC_SUBST([CODE_COVERAGE_RULES])
+	])
+
+	m4_ifdef([_AM_SUBST_NOTMAKE], [_AM_SUBST_NOTMAKE([CODE_COVERAGE_RULES])])
+])
diff --git a/src/c-ares/m4/ax_cxx_compile_stdcxx_11.m4 b/src/c-ares/m4/ax_cxx_compile_stdcxx_11.m4
new file mode 100644
index 000000000..229de3091
--- /dev/null
+++ b/src/c-ares/m4/ax_cxx_compile_stdcxx_11.m4
@@ -0,0 +1,163 @@
+# ============================================================================
+#  http://www.gnu.org/software/autoconf-archive/ax_cxx_compile_stdcxx_11.html
+# ============================================================================
+#
+# SYNOPSIS
+#
+#   AX_CXX_COMPILE_STDCXX_11([ext|noext],[mandatory|optional])
+#
+# DESCRIPTION
+#
+#   Check for baseline language coverage in the compiler for the C++11
+#   standard; if necessary, add switches to CXXFLAGS to enable support.
+#
+#   The first argument, if specified, indicates whether you insist on an
+#   extended mode (e.g. -std=gnu++11) or a strict conformance mode (e.g.
+#   -std=c++11).  If neither is specified, you get whatever works, with
+#   preference for an extended mode.
+#
+#   The second argument, if specified 'mandatory' or if left unspecified,
+#   indicates that baseline C++11 support is required and that the macro
+#   should error out if no mode with that support is found.  If specified
+#   'optional', then configuration proceeds regardless, after defining
+#   HAVE_CXX11 if and only if a supporting mode is found.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Benjamin Kosnik <bkoz@redhat.com>
+#   Copyright (c) 2012 Zack Weinberg <zackw@panix.com>
+#   Copyright (c) 2013 Roy Stogner <roystgnr@ices.utexas.edu>
+#   Copyright (c) 2014, 2015 Google Inc.; contributed by Alexey Sokolov <sokolov@google.com>
+#
+#   Copying and distribution of this file, with or without modification, are
+#   permitted in any medium without royalty provided the copyright notice
+#   and this notice are preserved. This file is offered as-is, without any
+#   warranty.
+
+#serial 9
+
+m4_define([_AX_CXX_COMPILE_STDCXX_11_testbody], [[
+  template <typename T>
+    struct check
+    {
+      static_assert(sizeof(int) <= sizeof(T), "not big enough");
+    };
+
+    struct Base {
+    virtual void f() {}
+    };
+    struct Child : public Base {
+    virtual void f() override {}
+    };
+
+    typedef check<check<bool>> right_angle_brackets;
+
+    int a;
+    decltype(a) b;
+
+    typedef check<int> check_type;
+    check_type c;
+    check_type&& cr = static_cast<check_type&&>(c);
+
+    auto d = a;
+    auto l = [](){};
+
+    // http://stackoverflow.com/questions/13728184/template-aliases-and-sfinae
+    // Clang 3.1 fails with headers of libstd++ 4.8.3 when using std::function because of this
+    namespace test_template_alias_sfinae {
+        struct foo {};
+
+        template<typename T>
+        using member = typename T::member_type;
+
+        template<typename T>
+        void func(...) {}
+
+        template<typename T>
+        void func(member<T>*) {}
+
+        void test();
+
+        void test() {
+            func<foo>(0);
+        }
+    }
+]])
+
+AC_DEFUN([AX_CXX_COMPILE_STDCXX_11], [dnl
+  m4_if([$1], [], [],
+        [$1], [ext], [],
+        [$1], [noext], [],
+        [m4_fatal([invalid argument `$1' to AX_CXX_COMPILE_STDCXX_11])])dnl
+  m4_if([$2], [], [ax_cxx_compile_cxx11_required=true],
+        [$2], [mandatory], [ax_cxx_compile_cxx11_required=true],
+        [$2], [optional], [ax_cxx_compile_cxx11_required=false],
+        [m4_fatal([invalid second argument `$2' to AX_CXX_COMPILE_STDCXX_11])])
+  AC_LANG_PUSH([C++])dnl
+  ac_success=no
+  AC_CACHE_CHECK(whether $CXX supports C++11 features by default,
+  ax_cv_cxx_compile_cxx11,
+  [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])],
+    [ax_cv_cxx_compile_cxx11=yes],
+    [ax_cv_cxx_compile_cxx11=no])])
+  if test x$ax_cv_cxx_compile_cxx11 = xyes; then
+    ac_success=yes
+  fi
+
+  m4_if([$1], [noext], [], [dnl
+  if test x$ac_success = xno; then
+    for switch in -std=gnu++11 -std=gnu++0x; do
+      cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx11_$switch])
+      AC_CACHE_CHECK(whether $CXX supports C++11 features with $switch,
+                     $cachevar,
+        [ac_save_CXXFLAGS="$CXXFLAGS"
+         CXXFLAGS="$CXXFLAGS $switch"
+         AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])],
+          [eval $cachevar=yes],
+          [eval $cachevar=no])
+         CXXFLAGS="$ac_save_CXXFLAGS"])
+      if eval test x\$$cachevar = xyes; then
+        CXXFLAGS="$CXXFLAGS $switch"
+        ac_success=yes
+        break
+      fi
+    done
+  fi])
+
+  m4_if([$1], [ext], [], [dnl
+  if test x$ac_success = xno; then
+    for switch in -std=c++11 -std=c++0x; do
+      cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx11_$switch])
+      AC_CACHE_CHECK(whether $CXX supports C++11 features with $switch,
+                     $cachevar,
+        [ac_save_CXXFLAGS="$CXXFLAGS"
+         CXXFLAGS="$CXXFLAGS $switch"
+         AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXX_COMPILE_STDCXX_11_testbody])],
+          [eval $cachevar=yes],
+          [eval $cachevar=no])
+         CXXFLAGS="$ac_save_CXXFLAGS"])
+      if eval test x\$$cachevar = xyes; then
+        CXXFLAGS="$CXXFLAGS $switch"
+        ac_success=yes
+        break
+      fi
+    done
+  fi])
+  AC_LANG_POP([C++])
+  if test x$ax_cxx_compile_cxx11_required = xtrue; then
+    if test x$ac_success = xno; then
+      AC_MSG_ERROR([*** A compiler with support for C++11 language features is required.])
+    fi
+  else
+    if test x$ac_success = xno; then
+      HAVE_CXX11=0
+      AC_MSG_NOTICE([No compiler with C++11 support was found])
+    else
+      HAVE_CXX11=1
+      AC_DEFINE(HAVE_CXX11,1,
+                [define if the compiler supports basic C++11 syntax])
+    fi
+
+    AC_SUBST(HAVE_CXX11)
+  fi
+])
diff --git a/src/c-ares/m4/ax_pthread.m4 b/src/c-ares/m4/ax_pthread.m4
new file mode 100644
index 000000000..d383ad5c6
--- /dev/null
+++ b/src/c-ares/m4/ax_pthread.m4
@@ -0,0 +1,332 @@
+# ===========================================================================
+#        http://www.gnu.org/software/autoconf-archive/ax_pthread.html
+# ===========================================================================
+#
+# SYNOPSIS
+#
+#   AX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]])
+#
+# DESCRIPTION
+#
+#   This macro figures out how to build C programs using POSIX threads. It
+#   sets the PTHREAD_LIBS output variable to the threads library and linker
+#   flags, and the PTHREAD_CFLAGS output variable to any special C compiler
+#   flags that are needed. (The user can also force certain compiler
+#   flags/libs to be tested by setting these environment variables.)
+#
+#   Also sets PTHREAD_CC to any special C compiler that is needed for
+#   multi-threaded programs (defaults to the value of CC otherwise). (This
+#   is necessary on AIX to use the special cc_r compiler alias.)
+#
+#   NOTE: You are assumed to not only compile your program with these flags,
+#   but also link it with them as well. e.g. you should link with
+#   $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS $LIBS
+#
+#   If you are only building threads programs, you may wish to use these
+#   variables in your default LIBS, CFLAGS, and CC:
+#
+#     LIBS="$PTHREAD_LIBS $LIBS"
+#     CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+#     CC="$PTHREAD_CC"
+#
+#   In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute constant
+#   has a nonstandard name, defines PTHREAD_CREATE_JOINABLE to that name
+#   (e.g. PTHREAD_CREATE_UNDETACHED on AIX).
+#
+#   Also HAVE_PTHREAD_PRIO_INHERIT is defined if pthread is found and the
+#   PTHREAD_PRIO_INHERIT symbol is defined when compiling with
+#   PTHREAD_CFLAGS.
+#
+#   ACTION-IF-FOUND is a list of shell commands to run if a threads library
+#   is found, and ACTION-IF-NOT-FOUND is a list of commands to run it if it
+#   is not found. If ACTION-IF-FOUND is not specified, the default action
+#   will define HAVE_PTHREAD.
+#
+#   Please let the authors know if this macro fails on any platform, or if
+#   you have any other suggestions or comments. This macro was based on work
+#   by SGJ on autoconf scripts for FFTW (http://www.fftw.org/) (with help
+#   from M. Frigo), as well as ac_pthread and hb_pthread macros posted by
+#   Alejandro Forero Cuervo to the autoconf macro repository. We are also
+#   grateful for the helpful feedback of numerous users.
+#
+#   Updated for Autoconf 2.68 by Daniel Richard G.
+#
+# LICENSE
+#
+#   Copyright (c) 2008 Steven G. Johnson <stevenj@alum.mit.edu>
+#   Copyright (c) 2011 Daniel Richard G. <skunk@iSKUNK.ORG>
+#
+#   This program is free software: you can redistribute it and/or modify it
+#   under the terms of the GNU General Public License as published by the
+#   Free Software Foundation, either version 3 of the License, or (at your
+#   option) any later version.
+#
+#   This program is distributed in the hope that it will be useful, but
+#   WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+#   Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License along
+#   with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+#   As a special exception, the respective Autoconf Macro's copyright owner
+#   gives unlimited permission to copy, distribute and modify the configure
+#   scripts that are the output of Autoconf when processing the Macro. You
+#   need not follow the terms of the GNU General Public License when using
+#   or distributing such scripts, even though portions of the text of the
+#   Macro appear in them. The GNU General Public License (GPL) does govern
+#   all other use of the material that constitutes the Autoconf Macro.
+#
+#   This special exception to the GPL applies to versions of the Autoconf
+#   Macro released by the Autoconf Archive. When you make and distribute a
+#   modified version of the Autoconf Macro, you may extend this special
+#   exception to the GPL to apply to your modified version as well.
+
+#serial 21
+
+AU_ALIAS([ACX_PTHREAD], [AX_PTHREAD])
+AC_DEFUN([AX_PTHREAD], [
+AC_REQUIRE([AC_CANONICAL_HOST])
+AC_LANG_PUSH([C])
+ax_pthread_ok=no
+
+# We used to check for pthread.h first, but this fails if pthread.h
+# requires special compiler flags (e.g. on True64 or Sequent).
+# It gets checked for in the link test anyway.
+
+# First of all, check if the user has set any of the PTHREAD_LIBS,
+# etcetera environment variables, and if threads linking works using
+# them:
+if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then
+        save_CFLAGS="$CFLAGS"
+        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+        save_LIBS="$LIBS"
+        LIBS="$PTHREAD_LIBS $LIBS"
+        AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS])
+        AC_TRY_LINK_FUNC([pthread_join], [ax_pthread_ok=yes])
+        AC_MSG_RESULT([$ax_pthread_ok])
+        if test x"$ax_pthread_ok" = xno; then
+                PTHREAD_LIBS=""
+                PTHREAD_CFLAGS=""
+        fi
+        LIBS="$save_LIBS"
+        CFLAGS="$save_CFLAGS"
+fi
+
+# We must check for the threads library under a number of different
+# names; the ordering is very important because some systems
+# (e.g. DEC) have both -lpthread and -lpthreads, where one of the
+# libraries is broken (non-POSIX).
+
+# Create a list of thread flags to try.  Items starting with a "-" are
+# C compiler flags, and other items are library names, except for "none"
+# which indicates that we try without any flags at all, and "pthread-config"
+# which is a program returning the flags for the Pth emulation library.
+
+ax_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
+
+# The ordering *is* (sometimes) important.  Some notes on the
+# individual items follow:
+
+# pthreads: AIX (must check this before -lpthread)
+# none: in case threads are in libc; should be tried before -Kthread and
+#       other compiler flags to prevent continual compiler warnings
+# -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)
+# -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
+# lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
+# -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads)
+# -pthreads: Solaris/gcc
+# -mthreads: Mingw32/gcc, Lynx/gcc
+# -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it
+#      doesn't hurt to check since this sometimes defines pthreads too;
+#      also defines -D_REENTRANT)
+#      ... -mt is also the pthreads flag for HP/aCC
+# pthread: Linux, etcetera
+# --thread-safe: KAI C++
+# pthread-config: use pthread-config program (for GNU Pth library)
+
+case ${host_os} in
+        solaris*)
+
+        # On Solaris (at least, for some versions), libc contains stubbed
+        # (non-functional) versions of the pthreads routines, so link-based
+        # tests will erroneously succeed.  (We need to link with -pthreads/-mt/
+        # -lpthread.)  (The stubs are missing pthread_cleanup_push, or rather
+        # a function called by this macro, so we could check for that, but
+        # who knows whether they'll stub that too in a future libc.)  So,
+        # we'll just look for -pthreads and -lpthread first:
+
+        ax_pthread_flags="-pthreads pthread -mt -pthread $ax_pthread_flags"
+        ;;
+
+        darwin*)
+        ax_pthread_flags="-pthread $ax_pthread_flags"
+        ;;
+esac
+
+# Clang doesn't consider unrecognized options an error unless we specify
+# -Werror. We throw in some extra Clang-specific options to ensure that
+# this doesn't happen for GCC, which also accepts -Werror.
+
+AC_MSG_CHECKING([if compiler needs -Werror to reject unknown flags])
+save_CFLAGS="$CFLAGS"
+ax_pthread_extra_flags="-Werror"
+CFLAGS="$CFLAGS $ax_pthread_extra_flags -Wunknown-warning-option -Wsizeof-array-argument"
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM([int foo(void);],[foo()])],
+                  [AC_MSG_RESULT([yes])],
+                  [ax_pthread_extra_flags=
+                   AC_MSG_RESULT([no])])
+CFLAGS="$save_CFLAGS"
+
+if test x"$ax_pthread_ok" = xno; then
+for flag in $ax_pthread_flags; do
+
+        case $flag in
+                none)
+                AC_MSG_CHECKING([whether pthreads work without any flags])
+                ;;
+
+                -*)
+                AC_MSG_CHECKING([whether pthreads work with $flag])
+                PTHREAD_CFLAGS="$flag"
+                ;;
+
+                pthread-config)
+                AC_CHECK_PROG([ax_pthread_config], [pthread-config], [yes], [no])
+                if test x"$ax_pthread_config" = xno; then continue; fi
+                PTHREAD_CFLAGS="`pthread-config --cflags`"
+                PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
+                ;;
+
+                *)
+                AC_MSG_CHECKING([for the pthreads library -l$flag])
+                PTHREAD_LIBS="-l$flag"
+                ;;
+        esac
+
+        save_LIBS="$LIBS"
+        save_CFLAGS="$CFLAGS"
+        LIBS="$PTHREAD_LIBS $LIBS"
+        CFLAGS="$CFLAGS $PTHREAD_CFLAGS $ax_pthread_extra_flags"
+
+        # Check for various functions.  We must include pthread.h,
+        # since some functions may be macros.  (On the Sequent, we
+        # need a special flag -Kthread to make this header compile.)
+        # We check for pthread_join because it is in -lpthread on IRIX
+        # while pthread_create is in libc.  We check for pthread_attr_init
+        # due to DEC craziness with -lpthreads.  We check for
+        # pthread_cleanup_push because it is one of the few pthread
+        # functions on Solaris that doesn't have a non-functional libc stub.
+        # We try pthread_create on general principles.
+        AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>
+                        static void routine(void *a) { a = 0; }
+                        static void *start_routine(void *a) { return a; }],
+                       [pthread_t th; pthread_attr_t attr;
+                        pthread_create(&th, 0, start_routine, 0);
+                        pthread_join(th, 0);
+                        pthread_attr_init(&attr);
+                        pthread_cleanup_push(routine, 0);
+                        pthread_cleanup_pop(0) /* ; */])],
+                [ax_pthread_ok=yes],
+                [])
+
+        LIBS="$save_LIBS"
+        CFLAGS="$save_CFLAGS"
+
+        AC_MSG_RESULT([$ax_pthread_ok])
+        if test "x$ax_pthread_ok" = xyes; then
+                break;
+        fi
+
+        PTHREAD_LIBS=""
+        PTHREAD_CFLAGS=""
+done
+fi
+
+# Various other checks:
+if test "x$ax_pthread_ok" = xyes; then
+        save_LIBS="$LIBS"
+        LIBS="$PTHREAD_LIBS $LIBS"
+        save_CFLAGS="$CFLAGS"
+        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+
+        # Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
+        AC_MSG_CHECKING([for joinable pthread attribute])
+        attr_name=unknown
+        for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
+            AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>],
+                           [int attr = $attr; return attr /* ; */])],
+                [attr_name=$attr; break],
+                [])
+        done
+        AC_MSG_RESULT([$attr_name])
+        if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then
+            AC_DEFINE_UNQUOTED([PTHREAD_CREATE_JOINABLE], [$attr_name],
+                               [Define to necessary symbol if this constant
+                                uses a non-standard name on your system.])
+        fi
+
+        AC_MSG_CHECKING([if more special flags are required for pthreads])
+        flag=no
+        case ${host_os} in
+            aix* | freebsd* | darwin*) flag="-D_THREAD_SAFE";;
+            osf* | hpux*) flag="-D_REENTRANT";;
+            solaris*)
+            if test "$GCC" = "yes"; then
+                flag="-D_REENTRANT"
+            else
+                # TODO: What about Clang on Solaris?
+                flag="-mt -D_REENTRANT"
+            fi
+            ;;
+        esac
+        AC_MSG_RESULT([$flag])
+        if test "x$flag" != xno; then
+            PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS"
+        fi
+
+        AC_CACHE_CHECK([for PTHREAD_PRIO_INHERIT],
+            [ax_cv_PTHREAD_PRIO_INHERIT], [
+                AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <pthread.h>]],
+                                                [[int i = PTHREAD_PRIO_INHERIT;]])],
+                    [ax_cv_PTHREAD_PRIO_INHERIT=yes],
+                    [ax_cv_PTHREAD_PRIO_INHERIT=no])
+            ])
+        AS_IF([test "x$ax_cv_PTHREAD_PRIO_INHERIT" = "xyes"],
+            [AC_DEFINE([HAVE_PTHREAD_PRIO_INHERIT], [1], [Have PTHREAD_PRIO_INHERIT.])])
+
+        LIBS="$save_LIBS"
+        CFLAGS="$save_CFLAGS"
+
+        # More AIX lossage: compile with *_r variant
+        if test "x$GCC" != xyes; then
+            case $host_os in
+                aix*)
+                AS_CASE(["x/$CC"],
+                  [x*/c89|x*/c89_128|x*/c99|x*/c99_128|x*/cc|x*/cc128|x*/xlc|x*/xlc_v6|x*/xlc128|x*/xlc128_v6],
+                  [#handle absolute path differently from PATH based program lookup
+                   AS_CASE(["x$CC"],
+                     [x/*],
+                     [AS_IF([AS_EXECUTABLE_P([${CC}_r])],[PTHREAD_CC="${CC}_r"])],
+                     [AC_CHECK_PROGS([PTHREAD_CC],[${CC}_r],[$CC])])])
+                ;;
+            esac
+        fi
+fi
+
+test -n "$PTHREAD_CC" || PTHREAD_CC="$CC"
+
+AC_SUBST([PTHREAD_LIBS])
+AC_SUBST([PTHREAD_CFLAGS])
+AC_SUBST([PTHREAD_CC])
+
+# Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
+if test x"$ax_pthread_ok" = xyes; then
+        ifelse([$1],,[AC_DEFINE([HAVE_PTHREAD],[1],[Define if you have POSIX threads libraries and header files.])],[$1])
+        :
+else
+        ax_pthread_ok=no
+        $2
+fi
+AC_LANG_POP
+])dnl AX_PTHREAD
diff --git a/src/c-ares/m4/cares-compilers.m4 b/src/c-ares/m4/cares-compilers.m4
new file mode 100644
index 000000000..2b98a6886
--- /dev/null
+++ b/src/c-ares/m4/cares-compilers.m4
@@ -0,0 +1,1587 @@
+#***************************************************************************
+#
+# Copyright (C) 2009-2013 by Daniel Stenberg et al
+#
+# Permission to use, copy, modify, and distribute this software and its
+# documentation for any purpose and without fee is hereby granted, provided
+# that the above copyright notice appear in all copies and that both that
+# copyright notice and this permission notice appear in supporting
+# documentation, and that the name of M.I.T. not be used in advertising or
+# publicity pertaining to distribution of the software without specific,
+# written prior permission.  M.I.T. makes no representations about the
+# suitability of this software for any purpose.  It is provided "as is"
+# without express or implied warranty.
+#
+#***************************************************************************
+
+# File version for 'aclocal' use. Keep it a single number.
+# serial 75
+
+
+dnl CARES_CHECK_COMPILER
+dnl -------------------------------------------------
+dnl Verify if the C compiler being used is known.
+
+AC_DEFUN([CARES_CHECK_COMPILER], [
+  #
+  compiler_id="unknown"
+  compiler_num="0"
+  #
+  flags_dbg_all="unknown"
+  flags_dbg_yes="unknown"
+  flags_dbg_off="unknown"
+  flags_opt_all="unknown"
+  flags_opt_yes="unknown"
+  flags_opt_off="unknown"
+  #
+  flags_prefer_cppflags="no"
+  #
+  CARES_CHECK_COMPILER_DEC_C
+  CARES_CHECK_COMPILER_HPUX_C
+  CARES_CHECK_COMPILER_IBM_C
+  CARES_CHECK_COMPILER_INTEL_C
+  CARES_CHECK_COMPILER_CLANG
+  CARES_CHECK_COMPILER_GNU_C
+  CARES_CHECK_COMPILER_LCC
+  CARES_CHECK_COMPILER_SGI_MIPSPRO_C
+  CARES_CHECK_COMPILER_SGI_MIPS_C
+  CARES_CHECK_COMPILER_SUNPRO_C
+  CARES_CHECK_COMPILER_TINY_C
+  CARES_CHECK_COMPILER_WATCOM_C
+  #
+  if test "$compiler_id" = "unknown"; then
+  cat <<_EOF 1>&2
+***
+*** Warning: This configure script does not have information about the
+*** compiler you are using, relative to the flags required to enable or
+*** disable generation of debug info, optimization options or warnings.
+***
+*** Whatever settings are present in CFLAGS will be used for this run.
+***
+*** If you wish to help the c-ares project to better support your compiler
+*** you can report this and the required info on the c-ares development
+*** mailing list: http://cool.haxx.se/mailman/listinfo/c-ares/
+***
+_EOF
+  fi
+])
+
+
+dnl CARES_CHECK_COMPILER_CLANG
+dnl -------------------------------------------------
+dnl Verify if compiler being used is clang.
+
+AC_DEFUN([CARES_CHECK_COMPILER_CLANG], [
+  AC_BEFORE([$0],[CARES_CHECK_COMPILER_GNU_C])dnl
+  AC_MSG_CHECKING([if compiler is clang])
+  CURL_CHECK_DEF([__clang__], [], [silent])
+  if test "$curl_cv_have_def___clang__" = "yes"; then
+    AC_MSG_RESULT([yes])
+    compiler_id="CLANG"
+    clangver=`$CC -dumpversion`
+    clangvhi=`echo $clangver | cut -d . -f1`
+    clangvlo=`echo $clangver | cut -d . -f2`
+    compiler_num=`(expr $clangvhi "*" 100 + $clangvlo) 2>/dev/null`
+    flags_dbg_all="-g -g0 -g1 -g2 -g3"
+    flags_dbg_all="$flags_dbg_all -ggdb"
+    flags_dbg_all="$flags_dbg_all -gstabs"
+    flags_dbg_all="$flags_dbg_all -gstabs+"
+    flags_dbg_all="$flags_dbg_all -gcoff"
+    flags_dbg_all="$flags_dbg_all -gxcoff"
+    flags_dbg_all="$flags_dbg_all -gdwarf-2"
+    flags_dbg_all="$flags_dbg_all -gvms"
+    flags_dbg_yes="-g"
+    flags_dbg_off="-g0"
+    flags_opt_all="-O -O0 -O1 -O2 -Os -O3 -O4"
+    flags_opt_yes="-Os"
+    flags_opt_off="-O0"
+  else
+    AC_MSG_RESULT([no])
+  fi
+])
+
+
+dnl CARES_CHECK_COMPILER_DEC_C
+dnl -------------------------------------------------
+dnl Verify if compiler being used is DEC C.
+
+AC_DEFUN([CARES_CHECK_COMPILER_DEC_C], [
+  AC_MSG_CHECKING([if compiler is DEC/Compaq/HP C])
+  CURL_CHECK_DEF([__DECC], [], [silent])
+  CURL_CHECK_DEF([__DECC_VER], [], [silent])
+  if test "$curl_cv_have_def___DECC" = "yes" &&
+    test "$curl_cv_have_def___DECC_VER" = "yes"; then
+    AC_MSG_RESULT([yes])
+    compiler_id="DEC_C"
+    flags_dbg_all="-g -g0 -g1 -g2 -g3"
+    flags_dbg_yes="-g2"
+    flags_dbg_off="-g0"
+    flags_opt_all="-O -O0 -O1 -O2 -O3 -O4"
+    flags_opt_yes="-O1"
+    flags_opt_off="-O0"
+  else
+    AC_MSG_RESULT([no])
+  fi
+])
+
+
+dnl CARES_CHECK_COMPILER_GNU_C
+dnl -------------------------------------------------
+dnl Verify if compiler being used is GNU C.
+
+AC_DEFUN([CARES_CHECK_COMPILER_GNU_C], [
+  AC_REQUIRE([CARES_CHECK_COMPILER_INTEL_C])dnl
+  AC_REQUIRE([CARES_CHECK_COMPILER_CLANG])dnl
+  AC_MSG_CHECKING([if compiler is GNU C])
+  CURL_CHECK_DEF([__GNUC__], [], [silent])
+  if test "$curl_cv_have_def___GNUC__" = "yes" &&
+    test "$compiler_id" = "unknown"; then
+    AC_MSG_RESULT([yes])
+    compiler_id="GNU_C"
+    gccver=`$CC -dumpversion`
+    gccvhi=`echo $gccver | cut -d . -f1`
+    gccvlo=`echo $gccver | cut -d . -f2`
+    compiler_num=`(expr $gccvhi "*" 100 + $gccvlo) 2>/dev/null`
+    flags_dbg_all="-g -g0 -g1 -g2 -g3"
+    flags_dbg_all="$flags_dbg_all -ggdb"
+    flags_dbg_all="$flags_dbg_all -gstabs"
+    flags_dbg_all="$flags_dbg_all -gstabs+"
+    flags_dbg_all="$flags_dbg_all -gcoff"
+    flags_dbg_all="$flags_dbg_all -gxcoff"
+    flags_dbg_all="$flags_dbg_all -gdwarf-2"
+    flags_dbg_all="$flags_dbg_all -gvms"
+    flags_dbg_yes="-g"
+    flags_dbg_off="-g0"
+    flags_opt_all="-O -O0 -O1 -O2 -O3 -Os"
+    flags_opt_yes="-O2"
+    flags_opt_off="-O0"
+    CURL_CHECK_DEF([_WIN32], [], [silent])
+  else
+    AC_MSG_RESULT([no])
+  fi
+])
+
+
+dnl CARES_CHECK_COMPILER_HPUX_C
+dnl -------------------------------------------------
+dnl Verify if compiler being used is HP-UX C.
+
+AC_DEFUN([CARES_CHECK_COMPILER_HPUX_C], [
+  AC_MSG_CHECKING([if compiler is HP-UX C])
+  CURL_CHECK_DEF([__HP_cc], [], [silent])
+  if test "$curl_cv_have_def___HP_cc" = "yes"; then
+    AC_MSG_RESULT([yes])
+    compiler_id="HP_UX_C"
+    flags_dbg_all="-g -s"
+    flags_dbg_yes="-g"
+    flags_dbg_off="-s"
+    flags_opt_all="-O +O0 +O1 +O2 +O3 +O4"
+    flags_opt_yes="+O2"
+    flags_opt_off="+O0"
+  else
+    AC_MSG_RESULT([no])
+  fi
+])
+
+
+dnl CARES_CHECK_COMPILER_IBM_C
+dnl -------------------------------------------------
+dnl Verify if compiler being used is IBM C.
+
+AC_DEFUN([CARES_CHECK_COMPILER_IBM_C], [
+  AC_MSG_CHECKING([if compiler is IBM C])
+  CURL_CHECK_DEF([__IBMC__], [], [silent])
+  if test "$curl_cv_have_def___IBMC__" = "yes"; then
+    AC_MSG_RESULT([yes])
+    compiler_id="IBM_C"
+    flags_dbg_all="-g -g0 -g1 -g2 -g3"
+    flags_dbg_yes="-g"
+    flags_dbg_off=""
+    flags_opt_all="-O -O0 -O1 -O2 -O3 -O4 -O5"
+    flags_opt_all="$flags_opt_all -qnooptimize"
+    flags_opt_all="$flags_opt_all -qoptimize=0"
+    flags_opt_all="$flags_opt_all -qoptimize=1"
+    flags_opt_all="$flags_opt_all -qoptimize=2"
+    flags_opt_all="$flags_opt_all -qoptimize=3"
+    flags_opt_all="$flags_opt_all -qoptimize=4"
+    flags_opt_all="$flags_opt_all -qoptimize=5"
+    flags_opt_yes="-O2"
+    flags_opt_off="-qnooptimize"
+    flags_prefer_cppflags="yes"
+  else
+    AC_MSG_RESULT([no])
+  fi
+])
+
+
+dnl CARES_CHECK_COMPILER_INTEL_C
+dnl -------------------------------------------------
+dnl Verify if compiler being used is Intel C.
+
+AC_DEFUN([CARES_CHECK_COMPILER_INTEL_C], [
+  AC_BEFORE([$0],[CARES_CHECK_COMPILER_GNU_C])dnl
+  AC_MSG_CHECKING([if compiler is Intel C])
+  CURL_CHECK_DEF([__INTEL_COMPILER], [], [silent])
+  if test "$curl_cv_have_def___INTEL_COMPILER" = "yes"; then
+    AC_MSG_RESULT([yes])
+    compiler_num="$curl_cv_def___INTEL_COMPILER"
+    CURL_CHECK_DEF([__unix__], [], [silent])
+    if test "$curl_cv_have_def___unix__" = "yes"; then
+      compiler_id="INTEL_UNIX_C"
+      flags_dbg_all="-g -g0"
+      flags_dbg_yes="-g"
+      flags_dbg_off="-g0"
+      flags_opt_all="-O -O0 -O1 -O2 -O3 -Os"
+      flags_opt_yes="-O2"
+      flags_opt_off="-O0"
+    else
+      compiler_id="INTEL_WINDOWS_C"
+      flags_dbg_all="/ZI /Zi /zI /zi /ZD /Zd /zD /zd /Z7 /z7 /Oy /Oy-"
+      flags_dbg_all="$flags_dbg_all /debug"
+      flags_dbg_all="$flags_dbg_all /debug:none"
+      flags_dbg_all="$flags_dbg_all /debug:minimal"
+      flags_dbg_all="$flags_dbg_all /debug:partial"
+      flags_dbg_all="$flags_dbg_all /debug:full"
+      flags_dbg_all="$flags_dbg_all /debug:semantic_stepping"
+      flags_dbg_all="$flags_dbg_all /debug:extended"
+      flags_dbg_yes="/Zi /Oy-"
+      flags_dbg_off="/debug:none /Oy-"
+      flags_opt_all="/O /O0 /O1 /O2 /O3 /Od /Og /Og- /Oi /Oi-"
+      flags_opt_yes="/O2"
+      flags_opt_off="/Od"
+    fi
+  else
+    AC_MSG_RESULT([no])
+  fi
+])
+
+
+dnl CARES_CHECK_COMPILER_LCC
+dnl -------------------------------------------------
+dnl Verify if compiler being used is LCC.
+
+AC_DEFUN([CARES_CHECK_COMPILER_LCC], [
+  AC_MSG_CHECKING([if compiler is LCC])
+  CURL_CHECK_DEF([__LCC__], [], [silent])
+  if test "$curl_cv_have_def___LCC__" = "yes"; then
+    AC_MSG_RESULT([yes])
+    compiler_id="LCC"
+    flags_dbg_all="-g"
+    flags_dbg_yes="-g"
+    flags_dbg_off=""
+    flags_opt_all=""
+    flags_opt_yes=""
+    flags_opt_off=""
+  else
+    AC_MSG_RESULT([no])
+  fi
+])
+
+
+dnl CARES_CHECK_COMPILER_SGI_MIPS_C
+dnl -------------------------------------------------
+dnl Verify if compiler being used is SGI MIPS C.
+
+AC_DEFUN([CARES_CHECK_COMPILER_SGI_MIPS_C], [
+  AC_REQUIRE([CARES_CHECK_COMPILER_SGI_MIPSPRO_C])dnl
+  AC_MSG_CHECKING([if compiler is SGI MIPS C])
+  CURL_CHECK_DEF([__GNUC__], [], [silent])
+  CURL_CHECK_DEF([__sgi], [], [silent])
+  if test "$curl_cv_have_def___GNUC__" = "no" &&
+    test "$curl_cv_have_def___sgi" = "yes" &&
+    test "$compiler_id" = "unknown"; then
+    AC_MSG_RESULT([yes])
+    compiler_id="SGI_MIPS_C"
+    flags_dbg_all="-g -g0 -g1 -g2 -g3"
+    flags_dbg_yes="-g"
+    flags_dbg_off="-g0"
+    flags_opt_all="-O -O0 -O1 -O2 -O3 -Ofast"
+    flags_opt_yes="-O2"
+    flags_opt_off="-O0"
+  else
+    AC_MSG_RESULT([no])
+  fi
+])
+
+
+dnl CARES_CHECK_COMPILER_SGI_MIPSPRO_C
+dnl -------------------------------------------------
+dnl Verify if compiler being used is SGI MIPSpro C.
+
+AC_DEFUN([CARES_CHECK_COMPILER_SGI_MIPSPRO_C], [
+  AC_BEFORE([$0],[CARES_CHECK_COMPILER_SGI_MIPS_C])dnl
+  AC_MSG_CHECKING([if compiler is SGI MIPSpro C])
+  CURL_CHECK_DEF([__GNUC__], [], [silent])
+  CURL_CHECK_DEF([_COMPILER_VERSION], [], [silent])
+  CURL_CHECK_DEF([_SGI_COMPILER_VERSION], [], [silent])
+  if test "$curl_cv_have_def___GNUC__" = "no" &&
+    (test "$curl_cv_have_def__SGI_COMPILER_VERSION" = "yes" ||
+     test "$curl_cv_have_def__COMPILER_VERSION" = "yes"); then
+    AC_MSG_RESULT([yes])
+    compiler_id="SGI_MIPSPRO_C"
+    flags_dbg_all="-g -g0 -g1 -g2 -g3"
+    flags_dbg_yes="-g"
+    flags_dbg_off="-g0"
+    flags_opt_all="-O -O0 -O1 -O2 -O3 -Ofast"
+    flags_opt_yes="-O2"
+    flags_opt_off="-O0"
+  else
+    AC_MSG_RESULT([no])
+  fi
+])
+
+
+dnl CARES_CHECK_COMPILER_SUNPRO_C
+dnl -------------------------------------------------
+dnl Verify if compiler being used is SunPro C.
+
+AC_DEFUN([CARES_CHECK_COMPILER_SUNPRO_C], [
+  AC_MSG_CHECKING([if compiler is SunPro C])
+  CURL_CHECK_DEF([__SUNPRO_C], [], [silent])
+  if test "$curl_cv_have_def___SUNPRO_C" = "yes"; then
+    AC_MSG_RESULT([yes])
+    compiler_id="SUNPRO_C"
+    flags_dbg_all="-g -s"
+    flags_dbg_yes="-g"
+    flags_dbg_off="-s"
+    flags_opt_all="-O -xO -xO1 -xO2 -xO3 -xO4 -xO5"
+    flags_opt_yes="-xO2"
+    flags_opt_off=""
+  else
+    AC_MSG_RESULT([no])
+  fi
+])
+
+
+dnl CARES_CHECK_COMPILER_TINY_C
+dnl -------------------------------------------------
+dnl Verify if compiler being used is Tiny C.
+
+AC_DEFUN([CARES_CHECK_COMPILER_TINY_C], [
+  AC_MSG_CHECKING([if compiler is Tiny C])
+  CURL_CHECK_DEF([__TINYC__], [], [silent])
+  if test "$curl_cv_have_def___TINYC__" = "yes"; then
+    AC_MSG_RESULT([yes])
+    compiler_id="TINY_C"
+    flags_dbg_all="-g -b"
+    flags_dbg_yes="-g"
+    flags_dbg_off=""
+    flags_opt_all=""
+    flags_opt_yes=""
+    flags_opt_off=""
+  else
+    AC_MSG_RESULT([no])
+  fi
+])
+
+
+dnl CARES_CHECK_COMPILER_WATCOM_C
+dnl -------------------------------------------------
+dnl Verify if compiler being used is Watcom C.
+
+AC_DEFUN([CARES_CHECK_COMPILER_WATCOM_C], [
+  AC_MSG_CHECKING([if compiler is Watcom C])
+  CURL_CHECK_DEF([__WATCOMC__], [], [silent])
+  if test "$curl_cv_have_def___WATCOMC__" = "yes"; then
+    AC_MSG_RESULT([yes])
+    CURL_CHECK_DEF([__UNIX__], [], [silent])
+    if test "$curl_cv_have_def___UNIX__" = "yes"; then
+      compiler_id="WATCOM_UNIX_C"
+      flags_dbg_all="-g1 -g1+ -g2 -g3"
+      flags_dbg_yes="-g2"
+      flags_dbg_off=""
+      flags_opt_all="-O0 -O1 -O2 -O3"
+      flags_opt_yes="-O2"
+      flags_opt_off="-O0"
+    else
+      compiler_id="WATCOM_WINDOWS_C"
+      flags_dbg_all=""
+      flags_dbg_yes=""
+      flags_dbg_off=""
+      flags_opt_all=""
+      flags_opt_yes=""
+      flags_opt_off=""
+    fi
+  else
+    AC_MSG_RESULT([no])
+  fi
+])
+
+
+dnl CARES_CONVERT_INCLUDE_TO_ISYSTEM
+dnl -------------------------------------------------
+dnl Changes standard include paths present in CFLAGS
+dnl and CPPFLAGS into isystem include paths. This is
+dnl done to prevent GNUC from generating warnings on
+dnl headers from these locations, although on ancient
+dnl GNUC versions these warnings are not silenced.
+
+AC_DEFUN([CARES_CONVERT_INCLUDE_TO_ISYSTEM], [
+  AC_REQUIRE([CARES_SHFUNC_SQUEEZE])dnl
+  AC_REQUIRE([CARES_CHECK_COMPILER])dnl
+  if test "$compiler_id" = "GNU_C" ||
+    test "$compiler_id" = "CLANG"; then
+    tmp_has_include="no"
+    tmp_chg_FLAGS="$CFLAGS"
+    for word1 in $tmp_chg_FLAGS; do
+      case "$word1" in
+        -I*)
+          tmp_has_include="yes"
+          ;;
+      esac
+    done
+    if test "$tmp_has_include" = "yes"; then
+      tmp_chg_FLAGS=`echo "$tmp_chg_FLAGS" | "$SED" 's/^-I/ -isystem /g'`
+      tmp_chg_FLAGS=`echo "$tmp_chg_FLAGS" | "$SED" 's/ -I/ -isystem /g'`
+      CFLAGS="$tmp_chg_FLAGS"
+      squeeze CFLAGS
+    fi
+    tmp_has_include="no"
+    tmp_chg_FLAGS="$CPPFLAGS"
+    for word1 in $tmp_chg_FLAGS; do
+      case "$word1" in
+        -I*)
+          tmp_has_include="yes"
+          ;;
+      esac
+    done
+    if test "$tmp_has_include" = "yes"; then
+      tmp_chg_FLAGS=`echo "$tmp_chg_FLAGS" | "$SED" 's/^-I/ -isystem /g'`
+      tmp_chg_FLAGS=`echo "$tmp_chg_FLAGS" | "$SED" 's/ -I/ -isystem /g'`
+      CPPFLAGS="$tmp_chg_FLAGS"
+      squeeze CPPFLAGS
+    fi
+  fi
+])
+
+
+dnl CARES_COMPILER_WORKS_IFELSE ([ACTION-IF-WORKS], [ACTION-IF-NOT-WORKS])
+dnl -------------------------------------------------
+dnl Verify if the C compiler seems to work with the
+dnl settings that are 'active' at the time the test
+dnl is performed.
+
+AC_DEFUN([CARES_COMPILER_WORKS_IFELSE], [
+  dnl compilation capability verification
+  tmp_compiler_works="unknown"
+  AC_COMPILE_IFELSE([
+    AC_LANG_PROGRAM([[
+    ]],[[
+      int i = 1;
+      return i;
+    ]])
+  ],[
+    tmp_compiler_works="yes"
+  ],[
+    tmp_compiler_works="no"
+    echo " " >&6
+    sed 's/^/cc-fail: /' conftest.err >&6
+    echo " " >&6
+  ])
+  dnl linking capability verification
+  if test "$tmp_compiler_works" = "yes"; then
+    AC_LINK_IFELSE([
+      AC_LANG_PROGRAM([[
+      ]],[[
+        int i = 1;
+        return i;
+      ]])
+    ],[
+      tmp_compiler_works="yes"
+    ],[
+      tmp_compiler_works="no"
+      echo " " >&6
+      sed 's/^/link-fail: /' conftest.err >&6
+      echo " " >&6
+    ])
+  fi
+  dnl only do runtime verification when not cross-compiling
+  if test "x$cross_compiling" != "xyes" &&
+    test "$tmp_compiler_works" = "yes"; then
+    AC_RUN_IFELSE([
+      AC_LANG_PROGRAM([[
+#       ifdef __STDC__
+#         include <stdlib.h>
+#       endif
+      ]],[[
+        int i = 0;
+        exit(i);
+      ]])
+    ],[
+      tmp_compiler_works="yes"
+    ],[
+      tmp_compiler_works="no"
+      echo " " >&6
+      echo "run-fail: test program exited with status $ac_status" >&6
+      echo " " >&6
+    ])
+  fi
+  dnl branch upon test result
+  if test "$tmp_compiler_works" = "yes"; then
+  ifelse($1,,:,[$1])
+  ifelse($2,,,[else
+    $2])
+  fi
+])
+
+
+dnl CARES_SET_COMPILER_BASIC_OPTS
+dnl -------------------------------------------------
+dnl Sets compiler specific options/flags which do not
+dnl depend on configure's debug, optimize or warnings
+dnl options.
+
+AC_DEFUN([CARES_SET_COMPILER_BASIC_OPTS], [
+  AC_REQUIRE([CARES_CHECK_COMPILER])dnl
+  AC_REQUIRE([CARES_SHFUNC_SQUEEZE])dnl
+  #
+  if test "$compiler_id" != "unknown"; then
+    #
+    if test "$compiler_id" = "GNU_C" ||
+      test "$compiler_id" = "CLANG"; then
+      CARES_CONVERT_INCLUDE_TO_ISYSTEM
+    fi
+    #
+    tmp_save_CPPFLAGS="$CPPFLAGS"
+    tmp_save_CFLAGS="$CFLAGS"
+    tmp_CPPFLAGS=""
+    tmp_CFLAGS=""
+    #
+    case "$compiler_id" in
+        #
+      CLANG)
+        #
+        dnl Disable warnings for unused arguments, otherwise clang will
+        dnl warn about compile-time arguments used during link-time, like
+        dnl -O and -g and -pedantic.
+        tmp_CFLAGS="$tmp_CFLAGS -Qunused-arguments"
+        ;;
+        #
+      DEC_C)
+        #
+        dnl Select strict ANSI C compiler mode
+        tmp_CFLAGS="$tmp_CFLAGS -std1"
+        dnl Turn off optimizer ANSI C aliasing rules
+        tmp_CFLAGS="$tmp_CFLAGS -noansi_alias"
+        dnl Generate warnings for missing function prototypes
+        tmp_CFLAGS="$tmp_CFLAGS -warnprotos"
+        dnl Change some warnings into fatal errors
+        tmp_CFLAGS="$tmp_CFLAGS -msg_fatal toofewargs,toomanyargs"
+        ;;
+        #
+      GNU_C)
+        #
+        dnl Placeholder
+        tmp_CFLAGS="$tmp_CFLAGS"
+        ;;
+        #
+      HP_UX_C)
+        #
+        dnl Disallow run-time dereferencing of null pointers
+        tmp_CFLAGS="$tmp_CFLAGS -z"
+        dnl Disable some remarks
+        dnl #4227: padding struct with n bytes to align member
+        dnl #4255: padding size of struct with n bytes to alignment boundary
+        tmp_CFLAGS="$tmp_CFLAGS +W 4227,4255"
+        ;;
+        #
+      IBM_C)
+        #
+        dnl Ensure that compiler optimizations are always thread-safe.
+        tmp_CPPFLAGS="$tmp_CPPFLAGS -qthreaded"
+        dnl Disable type based strict aliasing optimizations, using worst
+        dnl case aliasing assumptions when compiling. Type based aliasing
+        dnl would restrict the lvalues that could be safely used to access
+        dnl a data object.
+        tmp_CPPFLAGS="$tmp_CPPFLAGS -qnoansialias"
+        dnl Force compiler to stop after the compilation phase, without
+        dnl generating an object code file when compilation has errors.
+        tmp_CPPFLAGS="$tmp_CPPFLAGS -qhalt=e"
+        ;;
+        #
+      INTEL_UNIX_C)
+        #
+        dnl On unix this compiler uses gcc's header files, so
+        dnl we select ANSI C89 dialect plus GNU extensions.
+        tmp_CFLAGS="$tmp_CFLAGS -std=gnu89"
+        dnl Change some warnings into errors
+        dnl #140: too many arguments in function call
+        dnl #147: declaration is incompatible with 'previous one'
+        dnl #165: too few arguments in function call
+        dnl #266: function declared implicitly
+        tmp_CPPFLAGS="$tmp_CPPFLAGS -we 140,147,165,266"
+        dnl Disable some remarks
+        dnl #279: controlling expression is constant
+        dnl #981: operands are evaluated in unspecified order
+        dnl #1469: "cc" clobber ignored
+        tmp_CPPFLAGS="$tmp_CPPFLAGS -wd 279,981,1469"
+        ;;
+        #
+      INTEL_WINDOWS_C)
+        #
+        dnl Placeholder
+        tmp_CFLAGS="$tmp_CFLAGS"
+        ;;
+        #
+      LCC)
+        #
+        dnl Disallow run-time dereferencing of null pointers
+        tmp_CFLAGS="$tmp_CFLAGS -n"
+        ;;
+        #
+      SGI_MIPS_C)
+        #
+        dnl Placeholder
+        tmp_CFLAGS="$tmp_CFLAGS"
+        ;;
+        #
+      SGI_MIPSPRO_C)
+        #
+        dnl Placeholder
+        tmp_CFLAGS="$tmp_CFLAGS"
+        ;;
+        #
+      SUNPRO_C)
+        #
+        dnl Placeholder
+        tmp_CFLAGS="$tmp_CFLAGS"
+        ;;
+        #
+      TINY_C)
+        #
+        dnl Placeholder
+        tmp_CFLAGS="$tmp_CFLAGS"
+        ;;
+        #
+      WATCOM_UNIX_C)
+        #
+        dnl Placeholder
+        tmp_CFLAGS="$tmp_CFLAGS"
+        ;;
+        #
+      WATCOM_WINDOWS_C)
+        #
+        dnl Placeholder
+        tmp_CFLAGS="$tmp_CFLAGS"
+        ;;
+        #
+    esac
+    #
+    squeeze tmp_CPPFLAGS
+    squeeze tmp_CFLAGS
+    #
+    if test ! -z "$tmp_CFLAGS" || test ! -z "$tmp_CPPFLAGS"; then
+      AC_MSG_CHECKING([if compiler accepts some basic options])
+      CPPFLAGS="$tmp_save_CPPFLAGS $tmp_CPPFLAGS"
+      CFLAGS="$tmp_save_CFLAGS $tmp_CFLAGS"
+      squeeze CPPFLAGS
+      squeeze CFLAGS
+      CARES_COMPILER_WORKS_IFELSE([
+        AC_MSG_RESULT([yes])
+        AC_MSG_NOTICE([compiler options added: $tmp_CFLAGS $tmp_CPPFLAGS])
+      ],[
+        AC_MSG_RESULT([no])
+        AC_MSG_WARN([compiler options rejected: $tmp_CFLAGS $tmp_CPPFLAGS])
+        dnl restore initial settings
+        CPPFLAGS="$tmp_save_CPPFLAGS"
+        CFLAGS="$tmp_save_CFLAGS"
+      ])
+    fi
+    #
+  fi
+])
+
+
+dnl CARES_SET_COMPILER_DEBUG_OPTS
+dnl -------------------------------------------------
+dnl Sets compiler specific options/flags which depend
+dnl on configure's debug option.
+
+AC_DEFUN([CARES_SET_COMPILER_DEBUG_OPTS], [
+  AC_REQUIRE([CARES_CHECK_OPTION_DEBUG])dnl
+  AC_REQUIRE([CARES_CHECK_COMPILER])dnl
+  AC_REQUIRE([CARES_SHFUNC_SQUEEZE])dnl
+  #
+  if test "$compiler_id" != "unknown"; then
+    #
+    tmp_save_CFLAGS="$CFLAGS"
+    tmp_save_CPPFLAGS="$CPPFLAGS"
+    #
+    tmp_options=""
+    tmp_CFLAGS="$CFLAGS"
+    tmp_CPPFLAGS="$CPPFLAGS"
+    CARES_VAR_STRIP([tmp_CFLAGS],[$flags_dbg_all])
+    CARES_VAR_STRIP([tmp_CPPFLAGS],[$flags_dbg_all])
+    #
+    if test "$want_debug" = "yes"; then
+      AC_MSG_CHECKING([if compiler accepts debug enabling options])
+      tmp_options="$flags_dbg_yes"
+    fi
+    if test "$want_debug" = "no"; then
+      AC_MSG_CHECKING([if compiler accepts debug disabling options])
+      tmp_options="$flags_dbg_off"
+    fi
+    #
+    if test "$flags_prefer_cppflags" = "yes"; then
+      CPPFLAGS="$tmp_CPPFLAGS $tmp_options"
+      CFLAGS="$tmp_CFLAGS"
+    else
+      CPPFLAGS="$tmp_CPPFLAGS"
+      CFLAGS="$tmp_CFLAGS $tmp_options"
+    fi
+    squeeze CPPFLAGS
+    squeeze CFLAGS
+    CARES_COMPILER_WORKS_IFELSE([
+      AC_MSG_RESULT([yes])
+      AC_MSG_NOTICE([compiler options added: $tmp_options])
+    ],[
+      AC_MSG_RESULT([no])
+      AC_MSG_WARN([compiler options rejected: $tmp_options])
+      dnl restore initial settings
+      CPPFLAGS="$tmp_save_CPPFLAGS"
+      CFLAGS="$tmp_save_CFLAGS"
+    ])
+    #
+  fi
+])
+
+
+dnl CARES_SET_COMPILER_OPTIMIZE_OPTS
+dnl -------------------------------------------------
+dnl Sets compiler specific options/flags which depend
+dnl on configure's optimize option.
+
+AC_DEFUN([CARES_SET_COMPILER_OPTIMIZE_OPTS], [
+  AC_REQUIRE([CARES_CHECK_OPTION_OPTIMIZE])dnl
+  AC_REQUIRE([CARES_CHECK_COMPILER])dnl
+  AC_REQUIRE([CARES_SHFUNC_SQUEEZE])dnl
+  #
+  if test "$compiler_id" != "unknown"; then
+    #
+    tmp_save_CFLAGS="$CFLAGS"
+    tmp_save_CPPFLAGS="$CPPFLAGS"
+    #
+    tmp_options=""
+    tmp_CFLAGS="$CFLAGS"
+    tmp_CPPFLAGS="$CPPFLAGS"
+    honor_optimize_option="yes"
+    #
+    dnl If optimization request setting has not been explicitly specified,
+    dnl it has been derived from the debug setting and initially assumed.
+    dnl This initially assumed optimizer setting will finally be ignored
+    dnl if CFLAGS or CPPFLAGS already hold optimizer flags. This implies
+    dnl that an initially assumed optimizer setting might not be honored.
+    #
+    if test "$want_optimize" = "assume_no" ||
+       test "$want_optimize" = "assume_yes"; then
+      AC_MSG_CHECKING([if compiler optimizer assumed setting might be used])
+      CARES_VAR_MATCH_IFELSE([tmp_CFLAGS],[$flags_opt_all],[
+        honor_optimize_option="no"
+      ])
+      CARES_VAR_MATCH_IFELSE([tmp_CPPFLAGS],[$flags_opt_all],[
+        honor_optimize_option="no"
+      ])
+      AC_MSG_RESULT([$honor_optimize_option])
+      if test "$honor_optimize_option" = "yes"; then
+        if test "$want_optimize" = "assume_yes"; then
+          want_optimize="yes"
+        fi
+        if test "$want_optimize" = "assume_no"; then
+          want_optimize="no"
+        fi
+      fi
+    fi
+    #
+    if test "$honor_optimize_option" = "yes"; then
+      CARES_VAR_STRIP([tmp_CFLAGS],[$flags_opt_all])
+      CARES_VAR_STRIP([tmp_CPPFLAGS],[$flags_opt_all])
+      if test "$want_optimize" = "yes"; then
+        AC_MSG_CHECKING([if compiler accepts optimizer enabling options])
+        tmp_options="$flags_opt_yes"
+      fi
+      if test "$want_optimize" = "no"; then
+        AC_MSG_CHECKING([if compiler accepts optimizer disabling options])
+        tmp_options="$flags_opt_off"
+      fi
+      if test "$flags_prefer_cppflags" = "yes"; then
+        CPPFLAGS="$tmp_CPPFLAGS $tmp_options"
+        CFLAGS="$tmp_CFLAGS"
+      else
+        CPPFLAGS="$tmp_CPPFLAGS"
+        CFLAGS="$tmp_CFLAGS $tmp_options"
+      fi
+      squeeze CPPFLAGS
+      squeeze CFLAGS
+      CARES_COMPILER_WORKS_IFELSE([
+        AC_MSG_RESULT([yes])
+        AC_MSG_NOTICE([compiler options added: $tmp_options])
+      ],[
+        AC_MSG_RESULT([no])
+        AC_MSG_WARN([compiler options rejected: $tmp_options])
+        dnl restore initial settings
+        CPPFLAGS="$tmp_save_CPPFLAGS"
+        CFLAGS="$tmp_save_CFLAGS"
+      ])
+    fi
+    #
+  fi
+])
+
+
+dnl CARES_SET_COMPILER_WARNING_OPTS
+dnl -------------------------------------------------
+dnl Sets compiler options/flags which depend on
+dnl configure's warnings given option.
+
+AC_DEFUN([CARES_SET_COMPILER_WARNING_OPTS], [
+  AC_REQUIRE([CARES_CHECK_OPTION_WARNINGS])dnl
+  AC_REQUIRE([CARES_CHECK_COMPILER])dnl
+  AC_REQUIRE([CARES_SHFUNC_SQUEEZE])dnl
+  #
+  if test "$compiler_id" != "unknown"; then
+    #
+    tmp_save_CPPFLAGS="$CPPFLAGS"
+    tmp_save_CFLAGS="$CFLAGS"
+    tmp_CPPFLAGS=""
+    tmp_CFLAGS=""
+    #
+    case "$compiler_id" in
+        #
+      CLANG)
+        #
+        if test "$want_warnings" = "yes"; then
+          tmp_CFLAGS="$tmp_CFLAGS -pedantic"
+          tmp_CFLAGS="$tmp_CFLAGS -Wall -Wextra"
+          tmp_CFLAGS="$tmp_CFLAGS -Wpointer-arith -Wwrite-strings"
+          tmp_CFLAGS="$tmp_CFLAGS -Wshadow"
+          tmp_CFLAGS="$tmp_CFLAGS -Winline -Wnested-externs"
+          tmp_CFLAGS="$tmp_CFLAGS -Wmissing-declarations"
+          tmp_CFLAGS="$tmp_CFLAGS -Wmissing-prototypes"
+          tmp_CFLAGS="$tmp_CFLAGS -Wno-long-long"
+          tmp_CFLAGS="$tmp_CFLAGS -Wfloat-equal"
+          tmp_CFLAGS="$tmp_CFLAGS -Wno-multichar -Wsign-compare"
+          tmp_CFLAGS="$tmp_CFLAGS -Wundef"
+          tmp_CFLAGS="$tmp_CFLAGS -Wno-format-nonliteral"
+          tmp_CFLAGS="$tmp_CFLAGS -Wendif-labels -Wstrict-prototypes"
+          tmp_CFLAGS="$tmp_CFLAGS -Wdeclaration-after-statement"
+          tmp_CFLAGS="$tmp_CFLAGS -Wcast-align"
+          tmp_CFLAGS="$tmp_CFLAGS -Wno-system-headers"
+          tmp_CFLAGS="$tmp_CFLAGS -Wshorten-64-to-32"
+          #
+          dnl Only clang 1.1 or later
+          if test "$compiler_num" -ge "101"; then
+            tmp_CFLAGS="$tmp_CFLAGS -Wunused"
+          fi
+        fi
+        ;;
+        #
+      DEC_C)
+        #
+        if test "$want_warnings" = "yes"; then
+          dnl Select a higher warning level than default level2
+          tmp_CFLAGS="$tmp_CFLAGS -msg_enable level3"
+        fi
+        ;;
+        #
+      GNU_C)
+        #
+        if test "$want_warnings" = "yes"; then
+          #
+          dnl Do not enable -pedantic when cross-compiling with a gcc older
+          dnl than 3.0, to avoid warnings from third party system headers.
+          if test "x$cross_compiling" != "xyes" ||
+            test "$compiler_num" -ge "300"; then
+            tmp_CFLAGS="$tmp_CFLAGS -pedantic"
+          fi
+          #
+          dnl Set of options we believe *ALL* gcc versions support:
+          tmp_CFLAGS="$tmp_CFLAGS -Wall -W"
+          #
+          dnl Only gcc 1.4 or later
+          if test "$compiler_num" -ge "104"; then
+            tmp_CFLAGS="$tmp_CFLAGS -Wpointer-arith -Wwrite-strings"
+            dnl If not cross-compiling with a gcc older than 3.0
+            if test "x$cross_compiling" != "xyes" ||
+              test "$compiler_num" -ge "300"; then
+              tmp_CFLAGS="$tmp_CFLAGS -Wunused -Wshadow"
+            fi
+          fi
+          #
+          dnl Only gcc 2.7 or later
+          if test "$compiler_num" -ge "207"; then
+            tmp_CFLAGS="$tmp_CFLAGS -Winline -Wnested-externs"
+            dnl If not cross-compiling with a gcc older than 3.0
+            if test "x$cross_compiling" != "xyes" ||
+              test "$compiler_num" -ge "300"; then
+              tmp_CFLAGS="$tmp_CFLAGS -Wmissing-declarations"
+              tmp_CFLAGS="$tmp_CFLAGS -Wmissing-prototypes"
+            fi
+          fi
+          #
+          dnl Only gcc 2.95 or later
+          if test "$compiler_num" -ge "295"; then
+            tmp_CFLAGS="$tmp_CFLAGS -Wno-long-long"
+          fi
+          #
+          dnl Only gcc 2.96 or later
+          if test "$compiler_num" -ge "296"; then
+            tmp_CFLAGS="$tmp_CFLAGS -Wfloat-equal"
+            tmp_CFLAGS="$tmp_CFLAGS -Wno-multichar -Wsign-compare"
+            dnl -Wundef used only if gcc is 2.96 or later since we get
+            dnl lots of "`_POSIX_C_SOURCE' is not defined" in system
+            dnl headers with gcc 2.95.4 on FreeBSD 4.9
+            tmp_CFLAGS="$tmp_CFLAGS -Wundef"
+          fi
+          #
+          dnl Only gcc 2.97 or later
+          if test "$compiler_num" -ge "297"; then
+            tmp_CFLAGS="$tmp_CFLAGS -Wno-format-nonliteral"
+          fi
+          #
+          dnl Only gcc 3.0 or later
+          if test "$compiler_num" -ge "300"; then
+            dnl -Wunreachable-code seems totally unreliable on my gcc 3.3.2 on
+            dnl on i686-Linux as it gives us heaps with false positives.
+            dnl Also, on gcc 4.0.X it is totally unbearable and complains all
+            dnl over making it unusable for generic purposes. Let's not use it.
+            tmp_CFLAGS="$tmp_CFLAGS"
+          fi
+          #
+          dnl Only gcc 3.3 or later
+          if test "$compiler_num" -ge "303"; then
+            tmp_CFLAGS="$tmp_CFLAGS -Wendif-labels -Wstrict-prototypes"
+          fi
+          #
+          dnl Only gcc 3.4 or later
+          if test "$compiler_num" -ge "304"; then
+            tmp_CFLAGS="$tmp_CFLAGS -Wdeclaration-after-statement"
+          fi
+          #
+          dnl Only gcc 4.0 or later
+          if test "$compiler_num" -ge "400"; then
+            tmp_CFLAGS="$tmp_CFLAGS -Wstrict-aliasing=3"
+          fi
+          #
+          dnl Only gcc 4.2 or later
+          if test "$compiler_num" -ge "402"; then
+            tmp_CFLAGS="$tmp_CFLAGS -Wcast-align"
+          fi
+          #
+          dnl Only gcc 4.3 or later
+          if test "$compiler_num" -ge "403"; then
+            tmp_CFLAGS="$tmp_CFLAGS -Wtype-limits -Wold-style-declaration"
+            tmp_CFLAGS="$tmp_CFLAGS -Wmissing-parameter-type -Wempty-body"
+            tmp_CFLAGS="$tmp_CFLAGS -Wclobbered -Wignored-qualifiers"
+            tmp_CFLAGS="$tmp_CFLAGS -Wconversion -Wno-sign-conversion -Wvla"
+          fi
+          #
+          dnl Only gcc 4.5 or later
+          if test "$compiler_num" -ge "405"; then
+            dnl Only windows targets
+            if test "$curl_cv_have_def__WIN32" = "yes"; then
+              tmp_CFLAGS="$tmp_CFLAGS -Wno-pedantic-ms-format"
+            fi
+          fi
+          #
+        fi
+        #
+        dnl Do not issue warnings for code in system include paths.
+        if test "$compiler_num" -ge "300"; then
+          tmp_CFLAGS="$tmp_CFLAGS -Wno-system-headers"
+        else
+          dnl When cross-compiling with a gcc older than 3.0, disable
+          dnl some warnings triggered on third party system headers.
+          if test "x$cross_compiling" = "xyes"; then
+            if test "$compiler_num" -ge "104"; then
+              dnl gcc 1.4 or later
+              tmp_CFLAGS="$tmp_CFLAGS -Wno-unused -Wno-shadow"
+            fi
+            if test "$compiler_num" -ge "207"; then
+              dnl gcc 2.7 or later
+              tmp_CFLAGS="$tmp_CFLAGS -Wno-missing-declarations"
+              tmp_CFLAGS="$tmp_CFLAGS -Wno-missing-prototypes"
+            fi
+          fi
+        fi
+        ;;
+        #
+      HP_UX_C)
+        #
+        if test "$want_warnings" = "yes"; then
+          dnl Issue all warnings
+          tmp_CFLAGS="$tmp_CFLAGS +w1"
+        fi
+        ;;
+        #
+      IBM_C)
+        #
+        dnl Placeholder
+        tmp_CFLAGS="$tmp_CFLAGS"
+        ;;
+        #
+      INTEL_UNIX_C)
+        #
+        if test "$want_warnings" = "yes"; then
+          if test "$compiler_num" -gt "600"; then
+            dnl Show errors, warnings, and remarks
+            tmp_CPPFLAGS="$tmp_CPPFLAGS -Wall -w2"
+            dnl Perform extra compile-time code checking
+            tmp_CPPFLAGS="$tmp_CPPFLAGS -Wcheck"
+            dnl Warn on nested comments
+            tmp_CPPFLAGS="$tmp_CPPFLAGS -Wcomment"
+            dnl Show warnings relative to deprecated features
+            tmp_CPPFLAGS="$tmp_CPPFLAGS -Wdeprecated"
+            dnl Enable warnings for missing prototypes
+            tmp_CPPFLAGS="$tmp_CPPFLAGS -Wmissing-prototypes"
+            dnl Enable warnings for 64-bit portability issues
+            tmp_CPPFLAGS="$tmp_CPPFLAGS -Wp64"
+            dnl Enable warnings for questionable pointer arithmetic
+            tmp_CPPFLAGS="$tmp_CPPFLAGS -Wpointer-arith"
+            dnl Check for function return typw issues
+            tmp_CPPFLAGS="$tmp_CPPFLAGS -Wreturn-type"
+            dnl Warn on variable declarations hiding a previous one
+            tmp_CPPFLAGS="$tmp_CPPFLAGS -Wshadow"
+            dnl Warn when a variable is used before initialized
+            tmp_CPPFLAGS="$tmp_CPPFLAGS -Wuninitialized"
+            dnl Warn if a declared function is not used
+            tmp_CPPFLAGS="$tmp_CPPFLAGS -Wunused-function"
+          fi
+        fi
+        dnl Disable using EBP register in optimizations
+        tmp_CFLAGS="$tmp_CFLAGS -fno-omit-frame-pointer"
+        dnl Disable use of ANSI C aliasing rules in optimizations
+        tmp_CFLAGS="$tmp_CFLAGS -fno-strict-aliasing"
+        dnl Value-safe optimizations on floating-point data
+        tmp_CFLAGS="$tmp_CFLAGS -fp-model precise"
+        dnl Only icc 10.0 or later
+        if test "$compiler_num" -ge "1000"; then
+          dnl Disable vectorizer diagnostic information
+          tmp_CFLAGS="$tmp_CFLAGS -vec-report0"
+        fi
+        ;;
+        #
+      INTEL_WINDOWS_C)
+        #
+        dnl Placeholder
+        tmp_CFLAGS="$tmp_CFLAGS"
+        ;;
+        #
+      LCC)
+        #
+        if test "$want_warnings" = "yes"; then
+          dnl Highest warning level is double -A, next is single -A.
+          dnl Due to the big number of warnings these trigger on third
+          dnl party header files it is impractical for us to use any of
+          dnl them here. If you want them simply define it in CPPFLAGS.
+          tmp_CFLAGS="$tmp_CFLAGS"
+        fi
+        ;;
+        #
+      SGI_MIPS_C)
+        #
+        if test "$want_warnings" = "yes"; then
+          dnl Perform stricter semantic and lint-like checks
+          tmp_CFLAGS="$tmp_CFLAGS -fullwarn"
+        fi
+        ;;
+        #
+      SGI_MIPSPRO_C)
+        #
+        if test "$want_warnings" = "yes"; then
+          dnl Perform stricter semantic and lint-like checks
+          tmp_CFLAGS="$tmp_CFLAGS -fullwarn"
+          dnl Disable some remarks
+          dnl #1209: controlling expression is constant
+          tmp_CFLAGS="$tmp_CFLAGS -woff 1209"
+        fi
+        ;;
+        #
+      SUNPRO_C)
+        #
+        if test "$want_warnings" = "yes"; then
+          dnl Perform stricter semantic and lint-like checks
+          tmp_CFLAGS="$tmp_CFLAGS -v"
+        fi
+        ;;
+        #
+      TINY_C)
+        #
+        if test "$want_warnings" = "yes"; then
+          dnl Activate all warnings
+          tmp_CFLAGS="$tmp_CFLAGS -Wall"
+          dnl Make string constants be of type const char *
+          tmp_CFLAGS="$tmp_CFLAGS -Wwrite-strings"
+          dnl Warn use of unsupported GCC features ignored by TCC
+          tmp_CFLAGS="$tmp_CFLAGS -Wunsupported"
+        fi
+        ;;
+        #
+      WATCOM_UNIX_C)
+        #
+        if test "$want_warnings" = "yes"; then
+          dnl Issue all warnings
+          tmp_CFLAGS="$tmp_CFLAGS -Wall -Wextra"
+        fi
+        ;;
+        #
+      WATCOM_WINDOWS_C)
+        #
+        dnl Placeholder
+        tmp_CFLAGS="$tmp_CFLAGS"
+        ;;
+        #
+    esac
+    #
+    squeeze tmp_CPPFLAGS
+    squeeze tmp_CFLAGS
+    #
+    if test ! -z "$tmp_CFLAGS" || test ! -z "$tmp_CPPFLAGS"; then
+      AC_MSG_CHECKING([if compiler accepts strict warning options])
+      CPPFLAGS="$tmp_save_CPPFLAGS $tmp_CPPFLAGS"
+      CFLAGS="$tmp_save_CFLAGS $tmp_CFLAGS"
+      squeeze CPPFLAGS
+      squeeze CFLAGS
+      CARES_COMPILER_WORKS_IFELSE([
+        AC_MSG_RESULT([yes])
+        AC_MSG_NOTICE([compiler options added: $tmp_CFLAGS $tmp_CPPFLAGS])
+      ],[
+        AC_MSG_RESULT([no])
+        AC_MSG_WARN([compiler options rejected: $tmp_CFLAGS $tmp_CPPFLAGS])
+        dnl restore initial settings
+        CPPFLAGS="$tmp_save_CPPFLAGS"
+        CFLAGS="$tmp_save_CFLAGS"
+      ])
+    fi
+    #
+  fi
+])
+
+
+dnl CARES_SHFUNC_SQUEEZE
+dnl -------------------------------------------------
+dnl Declares a shell function squeeze() which removes
+dnl redundant whitespace out of a shell variable.
+
+AC_DEFUN([CARES_SHFUNC_SQUEEZE], [
+squeeze() {
+  _sqz_result=""
+  eval _sqz_input=\[$][$]1
+  for _sqz_token in $_sqz_input; do
+    if test -z "$_sqz_result"; then
+      _sqz_result="$_sqz_token"
+    else
+      _sqz_result="$_sqz_result $_sqz_token"
+    fi
+  done
+  eval [$]1=\$_sqz_result
+  return 0
+}
+])
+
+
+dnl CARES_CHECK_CURLDEBUG
+dnl -------------------------------------------------
+dnl Settings which depend on configure's curldebug given
+dnl option, and other additional configure pre-requisites.
+dnl Using the curl debug memory tracking feature in c-ares
+dnl is a hack that actually can only be used/enabled when
+dnl c-ares is built directly in curl's CVS tree, as a static
+dnl library or as a shared one on those systems on which
+dnl shared libraries support undefined symbols, along with
+dnl an equally configured libcurl.
+
+AC_DEFUN([CARES_CHECK_CURLDEBUG], [
+  AC_REQUIRE([XC_LIBTOOL])dnl
+  AC_REQUIRE([CARES_SHFUNC_SQUEEZE])dnl
+  cares_builddir=`pwd`
+  supports_curldebug="unknown"
+  if test "$want_curldebug" = "yes"; then
+    if test "x$enable_shared" != "xno" &&
+      test "x$enable_shared" != "xyes"; then
+      AC_MSG_WARN([unknown enable_shared setting.])
+      supports_curldebug="no"
+    fi
+    if test "x$enable_static" != "xno" &&
+      test "x$enable_static" != "xyes"; then
+      AC_MSG_WARN([unknown enable_static setting.])
+      supports_curldebug="no"
+    fi
+    if test "$supports_curldebug" != "no"; then
+      if test "$enable_shared" = "yes" &&
+        test "x$xc_lt_shlib_use_no_undefined" = 'xyes'; then
+        supports_curldebug="no"
+        AC_MSG_WARN([shared library does not support undefined symbols.])
+      fi
+      if test ! -f "$srcdir/../include/curl/curlbuild.h.dist"; then
+        AC_MSG_WARN([c-ares source not embedded in curl's CVS tree.])
+        supports_curldebug="no"
+      elif test ! -f "$srcdir/../include/curl/Makefile.in"; then
+        AC_MSG_WARN([curl's buildconf has not been run.])
+        supports_curldebug="no"
+      elif test ! -f "$cares_builddir/../libcurl.pc" ||
+        test ! -f "$cares_builddir/../include/curl/curlbuild.h"; then
+        AC_MSG_WARN([curl's configure has not been run.])
+        supports_curldebug="no"
+      elif test ! -f "$cares_builddir/../lib/curl_config.h"; then
+        AC_MSG_WARN([libcurl's curl_config.h is missing.])
+        supports_curldebug="no"
+      elif test ! -f "$cares_builddir/../config.status"; then
+        AC_MSG_WARN([curl's config.status is missing.])
+        supports_curldebug="no"
+      fi
+      if test "$supports_curldebug" != "no"; then
+        grep '^#define USE_ARES' "$cares_builddir/../lib/curl_config.h" >/dev/null
+        if test "$?" -ne "0"; then
+          AC_MSG_WARN([libcurl configured without c-ares support.])
+          supports_curldebug="no"
+        fi
+      fi
+      if test "$supports_curldebug" != "no"; then
+        grep 'CPPFLAGS.*CURLDEBUG' "$cares_builddir/../config.status" >/dev/null
+        if test "$?" -ne "0"; then
+          AC_MSG_WARN([libcurl configured without curldebug support.])
+          supports_curldebug="no"
+        fi
+      fi
+    fi
+  fi
+  #
+  if test "$want_curldebug" = "yes"; then
+    AC_MSG_CHECKING([if curl debug memory tracking can be enabled])
+    test "$supports_curldebug" = "no" || supports_curldebug="yes"
+    AC_MSG_RESULT([$supports_curldebug])
+    if test "$supports_curldebug" = "no"; then
+      AC_MSG_WARN([cannot enable curl debug memory tracking.])
+      want_curldebug="no"
+    fi
+  fi
+  #
+  if test "$want_curldebug" = "yes"; then
+    dnl TODO: Verify if the BUILDING_LIBCURL definition is still required.
+    AC_DEFINE(BUILDING_LIBCURL, 1, [when building as static part of libcurl])
+    CPPFLAGS="-DCURLDEBUG $CPPFLAGS"
+    squeeze CPPFLAGS
+  fi
+  #
+  if test "$want_debug" = "yes"; then
+    CPPFLAGS="-DDEBUGBUILD $CPPFLAGS"
+    squeeze CPPFLAGS
+  fi
+])
+
+
+dnl CARES_CHECK_COMPILER_HALT_ON_ERROR
+dnl -------------------------------------------------
+dnl Verifies if the compiler actually halts after the
+dnl compilation phase without generating any object
+dnl code file, when the source compiles with errors.
+
+AC_DEFUN([CARES_CHECK_COMPILER_HALT_ON_ERROR], [
+  AC_MSG_CHECKING([if compiler halts on compilation errors])
+  AC_COMPILE_IFELSE([
+    AC_LANG_PROGRAM([[
+    ]],[[
+      force compilation error
+    ]])
+  ],[
+    AC_MSG_RESULT([no])
+    AC_MSG_ERROR([compiler does not halt on compilation errors.])
+  ],[
+    AC_MSG_RESULT([yes])
+  ])
+])
+
+
+dnl CARES_CHECK_COMPILER_ARRAY_SIZE_NEGATIVE
+dnl -------------------------------------------------
+dnl Verifies if the compiler actually halts after the
+dnl compilation phase without generating any object
+dnl code file, when the source code tries to define a
+dnl type for a constant array with negative dimension.
+
+AC_DEFUN([CARES_CHECK_COMPILER_ARRAY_SIZE_NEGATIVE], [
+  AC_REQUIRE([CARES_CHECK_COMPILER_HALT_ON_ERROR])dnl
+  AC_MSG_CHECKING([if compiler halts on negative sized arrays])
+  AC_COMPILE_IFELSE([
+    AC_LANG_PROGRAM([[
+      typedef char bad_t[sizeof(char) == sizeof(int) ? -1 : -1 ];
+    ]],[[
+      bad_t dummy;
+    ]])
+  ],[
+    AC_MSG_RESULT([no])
+    AC_MSG_ERROR([compiler does not halt on negative sized arrays.])
+  ],[
+    AC_MSG_RESULT([yes])
+  ])
+])
+
+
+dnl CARES_CHECK_COMPILER_STRUCT_MEMBER_SIZE
+dnl -------------------------------------------------
+dnl Verifies if the compiler is capable of handling the
+dnl size of a struct member, struct which is a function
+dnl result, as a compilation-time condition inside the
+dnl type definition of a constant array.
+
+AC_DEFUN([CARES_CHECK_COMPILER_STRUCT_MEMBER_SIZE], [
+  AC_REQUIRE([CARES_CHECK_COMPILER_ARRAY_SIZE_NEGATIVE])dnl
+  AC_MSG_CHECKING([if compiler struct member size checking works])
+  tst_compiler_check_one_works="unknown"
+  AC_COMPILE_IFELSE([
+    AC_LANG_PROGRAM([[
+      struct mystruct {
+        int  mi;
+        char mc;
+        struct mystruct *next;
+      };
+      struct mystruct myfunc();
+      typedef char good_t1[sizeof(myfunc().mi) == sizeof(int)  ? 1 : -1 ];
+      typedef char good_t2[sizeof(myfunc().mc) == sizeof(char) ? 1 : -1 ];
+    ]],[[
+      good_t1 dummy1;
+      good_t2 dummy2;
+    ]])
+  ],[
+    tst_compiler_check_one_works="yes"
+  ],[
+    tst_compiler_check_one_works="no"
+    sed 's/^/cc-src: /' conftest.$ac_ext >&6
+    sed 's/^/cc-err: /' conftest.err >&6
+  ])
+  tst_compiler_check_two_works="unknown"
+  AC_COMPILE_IFELSE([
+    AC_LANG_PROGRAM([[
+      struct mystruct {
+        int  mi;
+        char mc;
+        struct mystruct *next;
+      };
+      struct mystruct myfunc();
+      typedef char bad_t1[sizeof(myfunc().mi) != sizeof(int)  ? 1 : -1 ];
+      typedef char bad_t2[sizeof(myfunc().mc) != sizeof(char) ? 1 : -1 ];
+    ]],[[
+      bad_t1 dummy1;
+      bad_t2 dummy2;
+    ]])
+  ],[
+    tst_compiler_check_two_works="no"
+  ],[
+    tst_compiler_check_two_works="yes"
+  ])
+  if test "$tst_compiler_check_one_works" = "yes" &&
+    test "$tst_compiler_check_two_works" = "yes"; then
+    AC_MSG_RESULT([yes])
+  else
+    AC_MSG_RESULT([no])
+    AC_MSG_ERROR([compiler fails struct member size checking.])
+  fi
+])
+
+
+dnl CARES_CHECK_COMPILER_SYMBOL_HIDING
+dnl -------------------------------------------------
+dnl Verify if compiler supports hiding library internal symbols, setting
+dnl shell variable supports_symbol_hiding value as appropriate, as well as
+dnl variables symbol_hiding_CFLAGS and symbol_hiding_EXTERN when supported.
+
+AC_DEFUN([CARES_CHECK_COMPILER_SYMBOL_HIDING], [
+  AC_REQUIRE([CARES_CHECK_COMPILER])dnl
+  AC_BEFORE([$0],[CARES_CONFIGURE_SYMBOL_HIDING])dnl
+  AC_MSG_CHECKING([if compiler supports hiding library internal symbols])
+  supports_symbol_hiding="no"
+  symbol_hiding_CFLAGS=""
+  symbol_hiding_EXTERN=""
+  tmp_CFLAGS=""
+  tmp_EXTERN=""
+  case "$compiler_id" in
+    CLANG)
+      dnl All versions of clang support -fvisibility=
+      tmp_EXTERN="__attribute__ ((__visibility__ (\"default\")))"
+      tmp_CFLAGS="-fvisibility=hidden"
+      supports_symbol_hiding="yes"
+      ;;
+    GNU_C)
+      dnl Only gcc 3.4 or later
+      if test "$compiler_num" -ge "304"; then
+        if $CC --help --verbose 2>&1 | grep fvisibility= > /dev/null ; then
+          tmp_EXTERN="__attribute__ ((__visibility__ (\"default\")))"
+          tmp_CFLAGS="-fvisibility=hidden"
+          supports_symbol_hiding="yes"
+        fi
+      fi
+      ;;
+    INTEL_UNIX_C)
+      dnl Only icc 9.0 or later
+      if test "$compiler_num" -ge "900"; then
+        if $CC --help --verbose 2>&1 | grep fvisibility= > /dev/null ; then
+          tmp_save_CFLAGS="$CFLAGS"
+          CFLAGS="$CFLAGS -fvisibility=hidden"
+          AC_LINK_IFELSE([
+            AC_LANG_PROGRAM([[
+#             include <stdio.h>
+            ]],[[
+              printf("icc fvisibility bug test");
+            ]])
+          ],[
+            tmp_EXTERN="__attribute__ ((__visibility__ (\"default\")))"
+            tmp_CFLAGS="-fvisibility=hidden"
+            supports_symbol_hiding="yes"
+          ])
+          CFLAGS="$tmp_save_CFLAGS"
+        fi
+      fi
+      ;;
+    SUNPRO_C)
+      if $CC 2>&1 | grep flags >/dev/null && $CC -flags | grep xldscope= >/dev/null ; then
+        tmp_EXTERN="__global"
+        tmp_CFLAGS="-xldscope=hidden"
+        supports_symbol_hiding="yes"
+      fi
+      ;;
+  esac
+  if test "$supports_symbol_hiding" = "yes"; then
+    tmp_save_CFLAGS="$CFLAGS"
+    CFLAGS="$tmp_save_CFLAGS $tmp_CFLAGS"
+    squeeze CFLAGS
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $tmp_EXTERN char *dummy(char *buff);
+        char *dummy(char *buff)
+        {
+         if(buff)
+           return ++buff;
+         else
+           return buff;
+        }
+      ]],[[
+        char b[16];
+        char *r = dummy(&b[0]);
+        if(r)
+          return (int)*r;
+      ]])
+    ],[
+      supports_symbol_hiding="yes"
+      if test -f conftest.err; then
+        grep 'visibility' conftest.err >/dev/null
+        if test "$?" -eq "0"; then
+          supports_symbol_hiding="no"
+        fi
+      fi
+    ],[
+      supports_symbol_hiding="no"
+      echo " " >&6
+      sed 's/^/cc-src: /' conftest.$ac_ext >&6
+      sed 's/^/cc-err: /' conftest.err >&6
+      echo " " >&6
+    ])
+    CFLAGS="$tmp_save_CFLAGS"
+  fi
+  if test "$supports_symbol_hiding" = "yes"; then
+    AC_MSG_RESULT([yes])
+    symbol_hiding_CFLAGS="$tmp_CFLAGS"
+    symbol_hiding_EXTERN="$tmp_EXTERN"
+  else
+    AC_MSG_RESULT([no])
+  fi
+])
+
+
+dnl CARES_CHECK_COMPILER_PROTOTYPE_MISMATCH
+dnl -------------------------------------------------
+dnl Verifies if the compiler actually halts after the
+dnl compilation phase without generating any object
+dnl code file, when the source code tries to redefine
+dnl a prototype which does not match previous one.
+
+AC_DEFUN([CARES_CHECK_COMPILER_PROTOTYPE_MISMATCH], [
+  AC_REQUIRE([CARES_CHECK_COMPILER_HALT_ON_ERROR])dnl
+  AC_MSG_CHECKING([if compiler halts on function prototype mismatch])
+  AC_COMPILE_IFELSE([
+    AC_LANG_PROGRAM([[
+#     include <stdlib.h>
+      int rand(int n);
+      int rand(int n)
+      {
+        if(n)
+          return ++n;
+        else
+          return n;
+      }
+    ]],[[
+      int i[2];
+      int j = rand(i[0]);
+      if(j)
+        return j;
+    ]])
+  ],[
+    AC_MSG_RESULT([no])
+    AC_MSG_ERROR([compiler does not halt on function prototype mismatch.])
+  ],[
+    AC_MSG_RESULT([yes])
+  ])
+])
+
+
+dnl CARES_VAR_MATCH (VARNAME, VALUE)
+dnl -------------------------------------------------
+dnl Verifies if shell variable VARNAME contains VALUE.
+dnl Contents of variable VARNAME and VALUE are handled
+dnl as whitespace separated lists of words. If at least
+dnl one word of VALUE is present in VARNAME the match
+dnl is considered positive, otherwise false.
+
+AC_DEFUN([CARES_VAR_MATCH], [
+  ac_var_match_word="no"
+  for word1 in $[$1]; do
+    for word2 in [$2]; do
+      if test "$word1" = "$word2"; then
+        ac_var_match_word="yes"
+      fi
+    done
+  done
+])
+
+
+dnl CARES_VAR_MATCH_IFELSE (VARNAME, VALUE,
+dnl                        [ACTION-IF-MATCH], [ACTION-IF-NOT-MATCH])
+dnl -------------------------------------------------
+dnl This performs a CURL_VAR_MATCH check and executes
+dnl first branch if the match is positive, otherwise
+dnl the second branch is executed.
+
+AC_DEFUN([CARES_VAR_MATCH_IFELSE], [
+  CARES_VAR_MATCH([$1],[$2])
+  if test "$ac_var_match_word" = "yes"; then
+  ifelse($3,,:,[$3])
+  ifelse($4,,,[else
+    $4])
+  fi
+])
+
+
+dnl CARES_VAR_STRIP (VARNAME, VALUE)
+dnl -------------------------------------------------
+dnl Contents of variable VARNAME and VALUE are handled
+dnl as whitespace separated lists of words. Each word
+dnl from VALUE is removed from VARNAME when present.
+
+AC_DEFUN([CARES_VAR_STRIP], [
+  AC_REQUIRE([CARES_SHFUNC_SQUEEZE])dnl
+  ac_var_stripped=""
+  for word1 in $[$1]; do
+    ac_var_strip_word="no"
+    for word2 in [$2]; do
+      if test "$word1" = "$word2"; then
+        ac_var_strip_word="yes"
+      fi
+    done
+    if test "$ac_var_strip_word" = "no"; then
+      ac_var_stripped="$ac_var_stripped $word1"
+    fi
+  done
+  dnl squeeze whitespace out of result
+  [$1]="$ac_var_stripped"
+  squeeze [$1]
+])
+
diff --git a/src/c-ares/m4/cares-confopts.m4 b/src/c-ares/m4/cares-confopts.m4
new file mode 100644
index 000000000..135036a74
--- /dev/null
+++ b/src/c-ares/m4/cares-confopts.m4
@@ -0,0 +1,396 @@
+#***************************************************************************
+#
+# Copyright (C) 2008 - 2013 by Daniel Stenberg et al
+#
+# Permission to use, copy, modify, and distribute this software and its
+# documentation for any purpose and without fee is hereby granted, provided
+# that the above copyright notice appear in all copies and that both that
+# copyright notice and this permission notice appear in supporting
+# documentation, and that the name of M.I.T. not be used in advertising or
+# publicity pertaining to distribution of the software without specific,
+# written prior permission.  M.I.T. makes no representations about the
+# suitability of this software for any purpose.  It is provided "as is"
+# without express or implied warranty.
+#
+#***************************************************************************
+
+# File version for 'aclocal' use. Keep it a single number.
+# serial 11
+
+
+dnl CARES_CHECK_OPTION_CURLDEBUG
+dnl -------------------------------------------------
+dnl Verify if configure has been invoked with option
+dnl --enable-curldebug or --disable-curldebug, and set
+dnl shell variable want_curldebug value as appropriate.
+
+AC_DEFUN([CARES_CHECK_OPTION_CURLDEBUG], [
+  AC_BEFORE([$0],[CARES_CHECK_CURLDEBUG])dnl
+  AC_MSG_CHECKING([whether to enable curl debug memory tracking])
+  OPT_CURLDEBUG_BUILD="default"
+  AC_ARG_ENABLE(curldebug,
+AC_HELP_STRING([--enable-curldebug],[Enable curl debug memory tracking])
+AC_HELP_STRING([--disable-curldebug],[Disable curl debug memory tracking]),
+  OPT_CURLDEBUG_BUILD=$enableval)
+  case "$OPT_CURLDEBUG_BUILD" in
+    no)
+      dnl --disable-curldebug option used
+      want_curldebug="no"
+      ;;
+    default)
+      dnl configure option not specified
+      want_curldebug="no"
+      ;;
+    *)
+      dnl --enable-curldebug option used.
+      dnl The use of this option value is a request to enable curl's
+      dnl debug memory tracking for the c-ares library. This is a big
+      dnl hack that can only be done when a whole bunch of requisites
+      dnl are simultaneously satisfied. Later on, these requisites are
+      dnl verified and if they are not fully satisfied the option will
+      dnl be ignored and act as if --disable-curldebug had been given
+      dnl setting shell variable want_curldebug to 'no'.
+      want_curldebug="yes"
+      ;;
+  esac
+  AC_MSG_RESULT([$want_curldebug])
+])
+
+
+dnl CARES_CHECK_OPTION_DEBUG
+dnl -------------------------------------------------
+dnl Verify if configure has been invoked with option
+dnl --enable-debug or --disable-debug, and set shell
+dnl variable want_debug value as appropriate.
+
+AC_DEFUN([CARES_CHECK_OPTION_DEBUG], [
+  AC_BEFORE([$0],[CARES_CHECK_OPTION_WARNINGS])dnl
+  AC_BEFORE([$0],[CARES_CHECK_OPTION_CURLDEBUG])dnl
+  AC_BEFORE([$0],[XC_CHECK_PROG_CC])dnl
+  AC_MSG_CHECKING([whether to enable debug build options])
+  OPT_DEBUG_BUILD="default"
+  AC_ARG_ENABLE(debug,
+AC_HELP_STRING([--enable-debug],[Enable debug build options])
+AC_HELP_STRING([--disable-debug],[Disable debug build options]),
+  OPT_DEBUG_BUILD=$enableval)
+  case "$OPT_DEBUG_BUILD" in
+    no)
+      dnl --disable-debug option used
+      want_debug="no"
+      ;;
+    default)
+      dnl configure option not specified
+      want_debug="no"
+      ;;
+    *)
+      dnl --enable-debug option used
+      want_debug="yes"
+      ;;
+  esac
+  AC_MSG_RESULT([$want_debug])
+])
+
+
+dnl CARES_CHECK_OPTION_NONBLOCKING
+dnl -------------------------------------------------
+dnl Verify if configure has been invoked with option
+dnl --enable-nonblocking or --disable-nonblocking, and
+dnl set shell variable want_nonblocking as appropriate.
+
+AC_DEFUN([CARES_CHECK_OPTION_NONBLOCKING], [
+  AC_BEFORE([$0],[CARES_CHECK_NONBLOCKING_SOCKET])dnl
+  AC_MSG_CHECKING([whether to enable non-blocking communications])
+  OPT_NONBLOCKING="default"
+  AC_ARG_ENABLE(nonblocking,
+AC_HELP_STRING([--enable-nonblocking],[Enable non-blocking communications])
+AC_HELP_STRING([--disable-nonblocking],[Disable non-blocking communications]),
+  OPT_NONBLOCKING=$enableval)
+  case "$OPT_NONBLOCKING" in
+    no)
+      dnl --disable-nonblocking option used
+      want_nonblocking="no"
+      ;;
+    default)
+      dnl configure option not specified
+      want_nonblocking="yes"
+      ;;
+    *)
+      dnl --enable-nonblocking option used
+      want_nonblocking="yes"
+      ;;
+  esac
+  AC_MSG_RESULT([$want_nonblocking])
+])
+
+
+dnl CARES_CHECK_OPTION_OPTIMIZE
+dnl -------------------------------------------------
+dnl Verify if configure has been invoked with option
+dnl --enable-optimize or --disable-optimize, and set
+dnl shell variable want_optimize value as appropriate.
+
+AC_DEFUN([CARES_CHECK_OPTION_OPTIMIZE], [
+  AC_REQUIRE([CARES_CHECK_OPTION_DEBUG])dnl
+  AC_BEFORE([$0],[XC_CHECK_PROG_CC])dnl
+  AC_MSG_CHECKING([whether to enable compiler optimizer])
+  OPT_COMPILER_OPTIMIZE="default"
+  AC_ARG_ENABLE(optimize,
+AC_HELP_STRING([--enable-optimize(=OPT)],[Enable compiler optimizations (default=-O2)])
+AC_HELP_STRING([--disable-optimize],[Disable compiler optimizations]),
+  OPT_COMPILER_OPTIMIZE=$enableval)
+  case "$OPT_COMPILER_OPTIMIZE" in
+    no)
+      dnl --disable-optimize option used. We will handle this as
+      dnl a request to disable compiler optimizations if possible.
+      dnl If the compiler is known CFLAGS and CPPFLAGS will be
+      dnl overridden, otherwise this can not be honored.
+      want_optimize="no"
+      AC_MSG_RESULT([no])
+      ;;
+    default)
+      dnl configure's optimize option not specified. Initially we will
+      dnl handle this as a a request contrary to configure's setting
+      dnl for --enable-debug. IOW, initially, for debug-enabled builds
+      dnl this will be handled as a request to disable optimizations if
+      dnl possible, and for debug-disabled builds this will be handled
+      dnl initially as a request to enable optimizations if possible.
+      dnl Finally, if the compiler is known and CFLAGS and CPPFLAGS do
+      dnl not have any optimizer flag the request will be honored, in
+      dnl any other case the request can not be honored.
+      dnl IOW, existing optimizer flags defined in CFLAGS or CPPFLAGS
+      dnl will always take precedence over any initial assumption.
+      if test "$want_debug" = "yes"; then
+        want_optimize="assume_no"
+        AC_MSG_RESULT([not specified (assuming no)])
+      else
+        want_optimize="assume_yes"
+        AC_MSG_RESULT([not specified (assuming yes)])
+      fi
+      ;;
+    *)
+      dnl --enable-optimize option used. We will handle this as
+      dnl a request to enable compiler optimizations if possible.
+      dnl If the compiler is known CFLAGS and CPPFLAGS will be
+      dnl overridden, otherwise this can not be honored.
+      want_optimize="yes"
+      AC_MSG_RESULT([yes])
+      ;;
+  esac
+])
+
+
+dnl CARES_CHECK_OPTION_SYMBOL_HIDING
+dnl -------------------------------------------------
+dnl Verify if configure has been invoked with option
+dnl --enable-symbol-hiding or --disable-symbol-hiding,
+dnl setting shell variable want_symbol_hiding value.
+
+AC_DEFUN([CARES_CHECK_OPTION_SYMBOL_HIDING], [
+  AC_BEFORE([$0],[CARES_CHECK_COMPILER_SYMBOL_HIDING])dnl
+  AC_MSG_CHECKING([whether to enable hiding of library internal symbols])
+  OPT_SYMBOL_HIDING="default"
+  AC_ARG_ENABLE(symbol-hiding,
+AC_HELP_STRING([--enable-symbol-hiding],[Enable hiding of library internal symbols])
+AC_HELP_STRING([--disable-symbol-hiding],[Disable hiding of library internal symbols]),
+  OPT_SYMBOL_HIDING=$enableval)
+  case "$OPT_SYMBOL_HIDING" in
+    no)
+      dnl --disable-symbol-hiding option used.
+      dnl This is an indication to not attempt hiding of library internal
+      dnl symbols. Default symbol visibility will be used, which normally
+      dnl exposes all library internal symbols.
+      want_symbol_hiding="no"
+      AC_MSG_RESULT([no])
+      ;;
+    default)
+      dnl configure's symbol-hiding option not specified.
+      dnl Handle this as if --enable-symbol-hiding option was given.
+      want_symbol_hiding="yes"
+      AC_MSG_RESULT([yes])
+      ;;
+    *)
+      dnl --enable-symbol-hiding option used.
+      dnl This is an indication to attempt hiding of library internal
+      dnl symbols. This is only supported on some compilers/linkers.
+      want_symbol_hiding="yes"
+      AC_MSG_RESULT([yes])
+      ;;
+  esac
+])
+
+
+dnl CARES_CHECK_OPTION_EXPOSE_STATICS
+dnl -------------------------------------------------
+dnl Verify if configure has been invoked with option
+dnl --enable-expose-statics or --disable-expose-statics,
+dnl setting shell variable want_expose_statics value.
+
+AC_DEFUN([CARES_CHECK_OPTION_EXPOSE_STATICS], [
+  AC_MSG_CHECKING([whether to expose internal static functions for testing])
+  OPT_EXPOSE_STATICS="default"
+  AC_ARG_ENABLE(expose-statics,
+AC_HELP_STRING([--enable-expose-statics],[Enable exposure of internal static functions for testing])
+AC_HELP_STRING([--disable-expose-statics],[Disable exposure of internal static functions for testing]),
+  OPT_EXPOSE_STATICS=$enableval)
+  case "$OPT_EXPOSE_STATICS" in
+    no)
+      dnl --disable-expose-statics option used.
+      want_expose_statics="no"
+      AC_MSG_RESULT([no])
+      ;;
+    default)
+      dnl configure's expose-statics option not specified.
+      dnl Handle this as if --disable-expose-statics option was given.
+      want_expose_statics="no"
+      AC_MSG_RESULT([no])
+      ;;
+    *)
+      dnl --enable-expose-statics option used.
+      want_expose_statics="yes"
+      AC_MSG_RESULT([yes])
+      ;;
+  esac
+  if test "$want_expose_statics" = "yes"; then
+    AC_DEFINE_UNQUOTED(CARES_EXPOSE_STATICS, 1,
+      [Defined for build that exposes internal static functions for testing.])
+  fi
+])
+
+
+dnl CARES_CHECK_OPTION_WARNINGS
+dnl -------------------------------------------------
+dnl Verify if configure has been invoked with option
+dnl --enable-warnings or --disable-warnings, and set
+dnl shell variable want_warnings as appropriate.
+
+AC_DEFUN([CARES_CHECK_OPTION_WARNINGS], [
+  AC_REQUIRE([CARES_CHECK_OPTION_DEBUG])dnl
+  AC_BEFORE([$0],[CARES_CHECK_OPTION_WERROR])dnl
+  AC_BEFORE([$0],[XC_CHECK_PROG_CC])dnl
+  AC_MSG_CHECKING([whether to enable strict compiler warnings])
+  OPT_COMPILER_WARNINGS="default"
+  AC_ARG_ENABLE(warnings,
+AC_HELP_STRING([--enable-warnings],[Enable strict compiler warnings])
+AC_HELP_STRING([--disable-warnings],[Disable strict compiler warnings]),
+  OPT_COMPILER_WARNINGS=$enableval)
+  case "$OPT_COMPILER_WARNINGS" in
+    no)
+      dnl --disable-warnings option used
+      want_warnings="no"
+      ;;
+    default)
+      dnl configure option not specified, so
+      dnl use same setting as --enable-debug
+      want_warnings="$want_debug"
+      ;;
+    *)
+      dnl --enable-warnings option used
+      want_warnings="yes"
+      ;;
+  esac
+  AC_MSG_RESULT([$want_warnings])
+])
+
+dnl CARES_CHECK_OPTION_WERROR
+dnl -------------------------------------------------
+dnl Verify if configure has been invoked with option
+dnl --enable-werror or --disable-werror, and set
+dnl shell variable want_werror as appropriate.
+
+AC_DEFUN([CARES_CHECK_OPTION_WERROR], [
+  AC_BEFORE([$0],[CARES_CHECK_COMPILER])dnl
+  AC_MSG_CHECKING([whether to enable compiler warnings as errors])
+  OPT_COMPILER_WERROR="default"
+  AC_ARG_ENABLE(werror,
+AC_HELP_STRING([--enable-werror],[Enable compiler warnings as errors])
+AC_HELP_STRING([--disable-werror],[Disable compiler warnings as errors]),
+  OPT_COMPILER_WERROR=$enableval)
+  case "$OPT_COMPILER_WERROR" in
+    no)
+      dnl --disable-werror option used
+      want_werror="no"
+      ;;
+    default)
+      dnl configure option not specified
+      want_werror="no"
+      ;;
+    *)
+      dnl --enable-werror option used
+      want_werror="yes"
+      ;;
+  esac
+  AC_MSG_RESULT([$want_werror])
+])
+
+
+dnl CARES_CHECK_NONBLOCKING_SOCKET
+dnl -------------------------------------------------
+dnl Check for how to set a socket into non-blocking state.
+
+AC_DEFUN([CARES_CHECK_NONBLOCKING_SOCKET], [
+  AC_REQUIRE([CARES_CHECK_OPTION_NONBLOCKING])dnl
+  AC_REQUIRE([CARES_CHECK_FUNC_FCNTL])dnl
+  AC_REQUIRE([CARES_CHECK_FUNC_IOCTL])dnl
+  AC_REQUIRE([CARES_CHECK_FUNC_IOCTLSOCKET])dnl
+  AC_REQUIRE([CARES_CHECK_FUNC_IOCTLSOCKET_CAMEL])dnl
+  AC_REQUIRE([CARES_CHECK_FUNC_SETSOCKOPT])dnl
+  #
+  tst_method="unknown"
+  if test "$want_nonblocking" = "yes"; then
+    AC_MSG_CHECKING([how to set a socket into non-blocking mode])
+    if test "x$ac_cv_func_fcntl_o_nonblock" = "xyes"; then
+      tst_method="fcntl O_NONBLOCK"
+    elif test "x$ac_cv_func_ioctl_fionbio" = "xyes"; then
+      tst_method="ioctl FIONBIO"
+    elif test "x$ac_cv_func_ioctlsocket_fionbio" = "xyes"; then
+      tst_method="ioctlsocket FIONBIO"
+    elif test "x$ac_cv_func_ioctlsocket_camel_fionbio" = "xyes"; then
+      tst_method="IoctlSocket FIONBIO"
+    elif test "x$ac_cv_func_setsockopt_so_nonblock" = "xyes"; then
+      tst_method="setsockopt SO_NONBLOCK"
+    fi
+    AC_MSG_RESULT([$tst_method])
+    if test "$tst_method" = "unknown"; then
+      AC_MSG_WARN([cannot determine non-blocking socket method.])
+    fi
+  fi
+  if test "$tst_method" = "unknown"; then
+    AC_DEFINE_UNQUOTED(USE_BLOCKING_SOCKETS, 1,
+      [Define to disable non-blocking sockets.])
+    AC_MSG_WARN([non-blocking sockets disabled.])
+  fi
+])
+
+
+dnl CARES_CONFIGURE_SYMBOL_HIDING
+dnl -------------------------------------------------
+dnl Depending on --enable-symbol-hiding or --disable-symbol-hiding
+dnl configure option, and compiler capability to actually honor such
+dnl option, this will modify compiler flags as appropriate and also
+dnl provide needed definitions for configuration and Makefile.am files.
+dnl This macro should not be used until all compilation tests have
+dnl been done to prevent interferences on other tests.
+
+AC_DEFUN([CARES_CONFIGURE_SYMBOL_HIDING], [
+  AC_MSG_CHECKING([whether hiding of library internal symbols will actually happen])
+  CFLAG_CARES_SYMBOL_HIDING=""
+  doing_symbol_hiding="no"
+  if test x"$ac_cv_native_windows" != "xyes" &&
+    test "$want_symbol_hiding" = "yes" &&
+    test "$supports_symbol_hiding" = "yes"; then
+    doing_symbol_hiding="yes"
+    CFLAG_CARES_SYMBOL_HIDING="$symbol_hiding_CFLAGS"
+    AC_DEFINE_UNQUOTED(CARES_SYMBOL_SCOPE_EXTERN, $symbol_hiding_EXTERN,
+      [Definition to make a library symbol externally visible.])
+    AC_MSG_RESULT([yes])
+  else
+    AC_MSG_RESULT([no])
+  fi
+  AM_CONDITIONAL(DOING_CARES_SYMBOL_HIDING, test x$doing_symbol_hiding = xyes)
+  AC_SUBST(CFLAG_CARES_SYMBOL_HIDING)
+  if test "$doing_symbol_hiding" = "yes"; then
+    AC_DEFINE_UNQUOTED(CARES_SYMBOL_HIDING, 1,
+      [Defined for build with symbol hiding.])
+  fi
+])
+
diff --git a/src/c-ares/m4/cares-functions.m4 b/src/c-ares/m4/cares-functions.m4
new file mode 100644
index 000000000..7c7c92b53
--- /dev/null
+++ b/src/c-ares/m4/cares-functions.m4
@@ -0,0 +1,3615 @@
+#***************************************************************************
+#
+# Copyright (C) 2008 - 2012 by Daniel Stenberg et al
+#
+# Permission to use, copy, modify, and distribute this software and its
+# documentation for any purpose and without fee is hereby granted, provided
+# that the above copyright notice appear in all copies and that both that
+# copyright notice and this permission notice appear in supporting
+# documentation, and that the name of M.I.T. not be used in advertising or
+# publicity pertaining to distribution of the software without specific,
+# written prior permission.  M.I.T. makes no representations about the
+# suitability of this software for any purpose.  It is provided "as is"
+# without express or implied warranty.
+#
+#***************************************************************************
+
+# File version for 'aclocal' use. Keep it a single number.
+# serial 46
+
+
+dnl CARES_INCLUDES_ARPA_INET
+dnl -------------------------------------------------
+dnl Set up variable with list of headers that must be
+dnl included when arpa/inet.h is to be included.
+
+AC_DEFUN([CARES_INCLUDES_ARPA_INET], [
+cares_includes_arpa_inet="\
+/* includes start */
+#ifdef HAVE_SYS_TYPES_H
+#  include <sys/types.h>
+#endif
+#ifdef HAVE_SYS_SOCKET_H
+#  include <sys/socket.h>
+#endif
+#ifdef HAVE_NETINET_IN_H
+#  include <netinet/in.h>
+#endif
+#ifdef HAVE_ARPA_INET_H
+#  include <arpa/inet.h>
+#endif
+/* includes end */"
+  AC_CHECK_HEADERS(
+    sys/types.h sys/socket.h netinet/in.h arpa/inet.h,
+    [], [], [$cares_includes_arpa_inet])
+])
+
+
+dnl CARES_INCLUDES_FCNTL
+dnl -------------------------------------------------
+dnl Set up variable with list of headers that must be
+dnl included when fcntl.h is to be included.
+
+AC_DEFUN([CARES_INCLUDES_FCNTL], [
+cares_includes_fcntl="\
+/* includes start */
+#ifdef HAVE_SYS_TYPES_H
+#  include <sys/types.h>
+#endif
+#ifdef HAVE_UNISTD_H
+#  include <unistd.h>
+#endif
+#ifdef HAVE_FCNTL_H
+#  include <fcntl.h>
+#endif
+/* includes end */"
+  AC_CHECK_HEADERS(
+    sys/types.h unistd.h fcntl.h,
+    [], [], [$cares_includes_fcntl])
+])
+
+
+dnl CARES_INCLUDES_NETDB
+dnl -------------------------------------------------
+dnl Set up variable with list of headers that must be
+dnl included when netdb.h is to be included.
+
+AC_DEFUN([CARES_INCLUDES_NETDB], [
+cares_includes_netdb="\
+/* includes start */
+#ifdef HAVE_SYS_TYPES_H
+#  include <sys/types.h>
+#endif
+#ifdef HAVE_NETDB_H
+#  include <netdb.h>
+#endif
+/* includes end */"
+  AC_CHECK_HEADERS(
+    sys/types.h netdb.h,
+    [], [], [$cares_includes_netdb])
+])
+
+
+dnl CARES_INCLUDES_SOCKET
+dnl -------------------------------------------------
+dnl Set up variable with list of headers that must be
+dnl included when socket.h is to be included.
+
+AC_DEFUN([CARES_INCLUDES_SOCKET], [
+cares_includes_socket="\
+/* includes start */
+#ifdef HAVE_SYS_TYPES_H
+#  include <sys/types.h>
+#endif
+#ifdef HAVE_SOCKET_H
+#  include <socket.h>
+#endif
+/* includes end */"
+  AC_CHECK_HEADERS(
+    sys/types.h socket.h,
+    [], [], [$cares_includes_socket])
+])
+
+
+dnl CARES_INCLUDES_STDLIB
+dnl -------------------------------------------------
+dnl Set up variable with list of headers that must be
+dnl included when stdlib.h is to be included.
+
+AC_DEFUN([CARES_INCLUDES_STDLIB], [
+cares_includes_stdlib="\
+/* includes start */
+#ifdef HAVE_SYS_TYPES_H
+#  include <sys/types.h>
+#endif
+#ifdef HAVE_STDLIB_H
+#  include <stdlib.h>
+#endif
+/* includes end */"
+  AC_CHECK_HEADERS(
+    sys/types.h stdlib.h,
+    [], [], [$cares_includes_stdlib])
+])
+
+
+dnl CARES_INCLUDES_STRING
+dnl -------------------------------------------------
+dnl Set up variable with list of headers that must be
+dnl included when string(s).h is to be included.
+
+AC_DEFUN([CARES_INCLUDES_STRING], [
+cares_includes_string="\
+/* includes start */
+#ifdef HAVE_SYS_TYPES_H
+#  include <sys/types.h>
+#endif
+#ifdef HAVE_STRING_H
+#  include <string.h>
+#endif
+#ifdef HAVE_STRINGS_H
+#  include <strings.h>
+#endif
+/* includes end */"
+  AC_CHECK_HEADERS(
+    sys/types.h string.h strings.h,
+    [], [], [$cares_includes_string])
+])
+
+
+dnl CARES_INCLUDES_STROPTS
+dnl -------------------------------------------------
+dnl Set up variable with list of headers that must be
+dnl included when stropts.h is to be included.
+
+AC_DEFUN([CARES_INCLUDES_STROPTS], [
+cares_includes_stropts="\
+/* includes start */
+#ifdef HAVE_SYS_TYPES_H
+#  include <sys/types.h>
+#endif
+#ifdef HAVE_UNISTD_H
+#  include <unistd.h>
+#endif
+#ifdef HAVE_SYS_SOCKET_H
+#  include <sys/socket.h>
+#endif
+#ifdef HAVE_SYS_IOCTL_H
+#  include <sys/ioctl.h>
+#endif
+#ifdef HAVE_STROPTS_H
+#  include <stropts.h>
+#endif
+/* includes end */"
+  AC_CHECK_HEADERS(
+    sys/types.h unistd.h sys/socket.h sys/ioctl.h stropts.h,
+    [], [], [$cares_includes_stropts])
+])
+
+
+dnl CARES_INCLUDES_SYS_SOCKET
+dnl -------------------------------------------------
+dnl Set up variable with list of headers that must be
+dnl included when sys/socket.h is to be included.
+
+AC_DEFUN([CARES_INCLUDES_SYS_SOCKET], [
+cares_includes_sys_socket="\
+/* includes start */
+#ifdef HAVE_SYS_TYPES_H
+#  include <sys/types.h>
+#endif
+#ifdef HAVE_SYS_SOCKET_H
+#  include <sys/socket.h>
+#endif
+/* includes end */"
+  AC_CHECK_HEADERS(
+    sys/types.h sys/socket.h,
+    [], [], [$cares_includes_sys_socket])
+])
+
+
+dnl CARES_INCLUDES_SYS_TYPES
+dnl -------------------------------------------------
+dnl Set up variable with list of headers that must be
+dnl included when sys/types.h is to be included.
+
+AC_DEFUN([CARES_INCLUDES_SYS_TYPES], [
+cares_includes_sys_types="\
+/* includes start */
+#ifdef HAVE_SYS_TYPES_H
+#  include <sys/types.h>
+#endif
+/* includes end */"
+  AC_CHECK_HEADERS(
+    sys/types.h,
+    [], [], [$cares_includes_sys_types])
+])
+
+
+dnl CARES_INCLUDES_SYS_UIO
+dnl -------------------------------------------------
+dnl Set up variable with list of headers that must be
+dnl included when sys/uio.h is to be included.
+
+AC_DEFUN([CARES_INCLUDES_SYS_UIO], [
+cares_includes_sys_uio="\
+/* includes start */
+#ifdef HAVE_SYS_TYPES_H
+#  include <sys/types.h>
+#endif
+#ifdef HAVE_SYS_UIO_H
+#  include <sys/uio.h>
+#endif
+/* includes end */"
+  AC_CHECK_HEADERS(
+    sys/types.h sys/uio.h,
+    [], [], [$cares_includes_sys_uio])
+])
+
+
+dnl CARES_INCLUDES_UNISTD
+dnl -------------------------------------------------
+dnl Set up variable with list of headers that must be
+dnl included when unistd.h is to be included.
+
+AC_DEFUN([CARES_INCLUDES_UNISTD], [
+cares_includes_unistd="\
+/* includes start */
+#ifdef HAVE_SYS_TYPES_H
+#  include <sys/types.h>
+#endif
+#ifdef HAVE_UNISTD_H
+#  include <unistd.h>
+#endif
+/* includes end */"
+  AC_CHECK_HEADERS(
+    sys/types.h unistd.h,
+    [], [], [$cares_includes_unistd])
+])
+
+
+dnl CARES_INCLUDES_WINSOCK2
+dnl -------------------------------------------------
+dnl Set up variable with list of headers that must be
+dnl included when winsock(2).h is to be included.
+
+AC_DEFUN([CARES_INCLUDES_WINSOCK2], [
+cares_includes_winsock2="\
+/* includes start */
+#ifdef HAVE_WINDOWS_H
+#  ifndef WIN32_LEAN_AND_MEAN
+#    define WIN32_LEAN_AND_MEAN
+#  endif
+#  include <windows.h>
+#  ifdef HAVE_WINSOCK2_H
+#    include <winsock2.h>
+#  else
+#    ifdef HAVE_WINSOCK_H
+#      include <winsock.h>
+#    endif
+#  endif
+#endif
+/* includes end */"
+  CURL_CHECK_HEADER_WINDOWS
+  CURL_CHECK_HEADER_WINSOCK
+  CURL_CHECK_HEADER_WINSOCK2
+])
+
+
+dnl CARES_INCLUDES_WS2TCPIP
+dnl -------------------------------------------------
+dnl Set up variable with list of headers that must be
+dnl included when ws2tcpip.h is to be included.
+
+AC_DEFUN([CARES_INCLUDES_WS2TCPIP], [
+cares_includes_ws2tcpip="\
+/* includes start */
+#ifdef HAVE_WINDOWS_H
+#  ifndef WIN32_LEAN_AND_MEAN
+#    define WIN32_LEAN_AND_MEAN
+#  endif
+#  include <windows.h>
+#  ifdef HAVE_WINSOCK2_H
+#    include <winsock2.h>
+#    ifdef HAVE_WS2TCPIP_H
+#       include <ws2tcpip.h>
+#    endif
+#  endif
+#endif
+/* includes end */"
+  CURL_CHECK_HEADER_WINDOWS
+  CURL_CHECK_HEADER_WINSOCK2
+  CURL_CHECK_HEADER_WS2TCPIP
+])
+
+
+dnl CARES_PREPROCESS_CALLCONV
+dnl -------------------------------------------------
+dnl Set up variable with a preprocessor block which
+dnl defines function calling convention.
+
+AC_DEFUN([CARES_PREPROCESS_CALLCONV], [
+cares_preprocess_callconv="\
+/* preprocess start */
+#ifdef HAVE_WINDOWS_H
+#  define FUNCALLCONV __stdcall
+#else
+#  define FUNCALLCONV
+#endif
+/* preprocess end */"
+])
+
+
+dnl CARES_CHECK_FUNC_CLOSESOCKET
+dnl -------------------------------------------------
+dnl Verify if closesocket is available, prototyped, and
+dnl can be compiled. If all of these are true, and
+dnl usage has not been previously disallowed with
+dnl shell variable cares_disallow_closesocket, then
+dnl HAVE_CLOSESOCKET will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_CLOSESOCKET], [
+  AC_REQUIRE([CARES_INCLUDES_WINSOCK2])dnl
+  AC_REQUIRE([CARES_INCLUDES_SOCKET])dnl
+  #
+  tst_links_closesocket="unknown"
+  tst_proto_closesocket="unknown"
+  tst_compi_closesocket="unknown"
+  tst_allow_closesocket="unknown"
+  #
+  AC_MSG_CHECKING([if closesocket can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_PROGRAM([[
+      $cares_includes_winsock2
+      $cares_includes_socket
+    ]],[[
+      if(0 != closesocket(0))
+        return 1;
+    ]])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_closesocket="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_closesocket="no"
+  ])
+  #
+  if test "$tst_links_closesocket" = "yes"; then
+    AC_MSG_CHECKING([if closesocket is prototyped])
+    AC_EGREP_CPP([closesocket],[
+      $cares_includes_winsock2
+      $cares_includes_socket
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_closesocket="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_closesocket="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_closesocket" = "yes"; then
+    AC_MSG_CHECKING([if closesocket is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_winsock2
+        $cares_includes_socket
+      ]],[[
+        if(0 != closesocket(0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_closesocket="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_closesocket="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_closesocket" = "yes"; then
+    AC_MSG_CHECKING([if closesocket usage allowed])
+    if test "x$cares_disallow_closesocket" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_closesocket="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_closesocket="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if closesocket might be used])
+  if test "$tst_links_closesocket" = "yes" &&
+     test "$tst_proto_closesocket" = "yes" &&
+     test "$tst_compi_closesocket" = "yes" &&
+     test "$tst_allow_closesocket" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_CLOSESOCKET, 1,
+      [Define to 1 if you have the closesocket function.])
+    ac_cv_func_closesocket="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_closesocket="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_CLOSESOCKET_CAMEL
+dnl -------------------------------------------------
+dnl Verify if CloseSocket is available, prototyped, and
+dnl can be compiled. If all of these are true, and
+dnl usage has not been previously disallowed with
+dnl shell variable cares_disallow_closesocket_camel,
+dnl then HAVE_CLOSESOCKET_CAMEL will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_CLOSESOCKET_CAMEL], [
+  AC_REQUIRE([CARES_INCLUDES_SYS_SOCKET])dnl
+  #
+  tst_links_closesocket_camel="unknown"
+  tst_proto_closesocket_camel="unknown"
+  tst_compi_closesocket_camel="unknown"
+  tst_allow_closesocket_camel="unknown"
+  #
+  AC_MSG_CHECKING([if CloseSocket can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_PROGRAM([[
+      $cares_includes_sys_socket
+    ]],[[
+      if(0 != CloseSocket(0))
+        return 1;
+    ]])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_closesocket_camel="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_closesocket_camel="no"
+  ])
+  #
+  if test "$tst_links_closesocket_camel" = "yes"; then
+    AC_MSG_CHECKING([if CloseSocket is prototyped])
+    AC_EGREP_CPP([CloseSocket],[
+      $cares_includes_sys_socket
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_closesocket_camel="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_closesocket_camel="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_closesocket_camel" = "yes"; then
+    AC_MSG_CHECKING([if CloseSocket is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_sys_socket
+      ]],[[
+        if(0 != CloseSocket(0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_closesocket_camel="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_closesocket_camel="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_closesocket_camel" = "yes"; then
+    AC_MSG_CHECKING([if CloseSocket usage allowed])
+    if test "x$cares_disallow_closesocket_camel" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_closesocket_camel="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_closesocket_camel="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if CloseSocket might be used])
+  if test "$tst_links_closesocket_camel" = "yes" &&
+     test "$tst_proto_closesocket_camel" = "yes" &&
+     test "$tst_compi_closesocket_camel" = "yes" &&
+     test "$tst_allow_closesocket_camel" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_CLOSESOCKET_CAMEL, 1,
+      [Define to 1 if you have the CloseSocket camel case function.])
+    ac_cv_func_closesocket_camel="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_closesocket_camel="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_CONNECT
+dnl -------------------------------------------------
+dnl Verify if connect is available, prototyped, and
+dnl can be compiled. If all of these are true, and
+dnl usage has not been previously disallowed with
+dnl shell variable cares_disallow_connect, then
+dnl HAVE_CONNECT will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_CONNECT], [
+  AC_REQUIRE([CARES_INCLUDES_WINSOCK2])dnl
+  AC_REQUIRE([CARES_INCLUDES_SYS_SOCKET])dnl
+  AC_REQUIRE([CARES_INCLUDES_SOCKET])dnl
+  #
+  tst_links_connect="unknown"
+  tst_proto_connect="unknown"
+  tst_compi_connect="unknown"
+  tst_allow_connect="unknown"
+  #
+  AC_MSG_CHECKING([if connect can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_PROGRAM([[
+      $cares_includes_winsock2
+      $cares_includes_sys_socket
+      $cares_includes_socket
+    ]],[[
+      if(0 != connect(0, 0, 0))
+        return 1;
+    ]])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_connect="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_connect="no"
+  ])
+  #
+  if test "$tst_links_connect" = "yes"; then
+    AC_MSG_CHECKING([if connect is prototyped])
+    AC_EGREP_CPP([connect],[
+      $cares_includes_winsock2
+      $cares_includes_sys_socket
+      $cares_includes_socket
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_connect="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_connect="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_connect" = "yes"; then
+    AC_MSG_CHECKING([if connect is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_winsock2
+        $cares_includes_sys_socket
+        $cares_includes_socket
+      ]],[[
+        if(0 != connect(0, 0, 0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_connect="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_connect="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_connect" = "yes"; then
+    AC_MSG_CHECKING([if connect usage allowed])
+    if test "x$cares_disallow_connect" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_connect="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_connect="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if connect might be used])
+  if test "$tst_links_connect" = "yes" &&
+     test "$tst_proto_connect" = "yes" &&
+     test "$tst_compi_connect" = "yes" &&
+     test "$tst_allow_connect" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_CONNECT, 1,
+      [Define to 1 if you have the connect function.])
+    ac_cv_func_connect="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_connect="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_FCNTL
+dnl -------------------------------------------------
+dnl Verify if fcntl is available, prototyped, and
+dnl can be compiled. If all of these are true, and
+dnl usage has not been previously disallowed with
+dnl shell variable cares_disallow_fcntl, then
+dnl HAVE_FCNTL will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_FCNTL], [
+  AC_REQUIRE([CARES_INCLUDES_FCNTL])dnl
+  #
+  tst_links_fcntl="unknown"
+  tst_proto_fcntl="unknown"
+  tst_compi_fcntl="unknown"
+  tst_allow_fcntl="unknown"
+  #
+  AC_MSG_CHECKING([if fcntl can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([fcntl])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_fcntl="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_fcntl="no"
+  ])
+  #
+  if test "$tst_links_fcntl" = "yes"; then
+    AC_MSG_CHECKING([if fcntl is prototyped])
+    AC_EGREP_CPP([fcntl],[
+      $cares_includes_fcntl
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_fcntl="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_fcntl="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_fcntl" = "yes"; then
+    AC_MSG_CHECKING([if fcntl is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_fcntl
+      ]],[[
+        if(0 != fcntl(0, 0, 0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_fcntl="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_fcntl="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_fcntl" = "yes"; then
+    AC_MSG_CHECKING([if fcntl usage allowed])
+    if test "x$cares_disallow_fcntl" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_fcntl="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_fcntl="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if fcntl might be used])
+  if test "$tst_links_fcntl" = "yes" &&
+     test "$tst_proto_fcntl" = "yes" &&
+     test "$tst_compi_fcntl" = "yes" &&
+     test "$tst_allow_fcntl" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_FCNTL, 1,
+      [Define to 1 if you have the fcntl function.])
+    ac_cv_func_fcntl="yes"
+    CARES_CHECK_FUNC_FCNTL_O_NONBLOCK
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_fcntl="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_FCNTL_O_NONBLOCK
+dnl -------------------------------------------------
+dnl Verify if fcntl with status flag O_NONBLOCK is
+dnl available, can be compiled, and seems to work. If
+dnl all of these are true, then HAVE_FCNTL_O_NONBLOCK
+dnl will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_FCNTL_O_NONBLOCK], [
+  #
+  tst_compi_fcntl_o_nonblock="unknown"
+  tst_allow_fcntl_o_nonblock="unknown"
+  #
+  case $host_os in
+    sunos4* | aix3* | beos*)
+      dnl O_NONBLOCK does not work on these platforms
+      cares_disallow_fcntl_o_nonblock="yes"
+      ;;
+  esac
+  #
+  if test "$ac_cv_func_fcntl" = "yes"; then
+    AC_MSG_CHECKING([if fcntl O_NONBLOCK is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_fcntl
+      ]],[[
+        int flags = 0;
+        if(0 != fcntl(0, F_SETFL, flags | O_NONBLOCK))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_fcntl_o_nonblock="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_fcntl_o_nonblock="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_fcntl_o_nonblock" = "yes"; then
+    AC_MSG_CHECKING([if fcntl O_NONBLOCK usage allowed])
+    if test "x$cares_disallow_fcntl_o_nonblock" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_fcntl_o_nonblock="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_fcntl_o_nonblock="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if fcntl O_NONBLOCK might be used])
+  if test "$tst_compi_fcntl_o_nonblock" = "yes" &&
+     test "$tst_allow_fcntl_o_nonblock" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_FCNTL_O_NONBLOCK, 1,
+      [Define to 1 if you have a working fcntl O_NONBLOCK function.])
+    ac_cv_func_fcntl_o_nonblock="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_fcntl_o_nonblock="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_FREEADDRINFO
+dnl -------------------------------------------------
+dnl Verify if freeaddrinfo is available, prototyped,
+dnl and can be compiled. If all of these are true,
+dnl and usage has not been previously disallowed with
+dnl shell variable cares_disallow_freeaddrinfo, then
+dnl HAVE_FREEADDRINFO will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_FREEADDRINFO], [
+  AC_REQUIRE([CARES_INCLUDES_WS2TCPIP])dnl
+  AC_REQUIRE([CARES_INCLUDES_SYS_SOCKET])dnl
+  AC_REQUIRE([CARES_INCLUDES_NETDB])dnl
+  #
+  tst_links_freeaddrinfo="unknown"
+  tst_proto_freeaddrinfo="unknown"
+  tst_compi_freeaddrinfo="unknown"
+  tst_allow_freeaddrinfo="unknown"
+  #
+  AC_MSG_CHECKING([if freeaddrinfo can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_PROGRAM([[
+      $cares_includes_ws2tcpip
+      $cares_includes_sys_socket
+      $cares_includes_netdb
+    ]],[[
+      freeaddrinfo(0);
+    ]])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_freeaddrinfo="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_freeaddrinfo="no"
+  ])
+  #
+  if test "$tst_links_freeaddrinfo" = "yes"; then
+    AC_MSG_CHECKING([if freeaddrinfo is prototyped])
+    AC_EGREP_CPP([freeaddrinfo],[
+      $cares_includes_ws2tcpip
+      $cares_includes_sys_socket
+      $cares_includes_netdb
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_freeaddrinfo="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_freeaddrinfo="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_freeaddrinfo" = "yes"; then
+    AC_MSG_CHECKING([if freeaddrinfo is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_ws2tcpip
+        $cares_includes_sys_socket
+        $cares_includes_netdb
+      ]],[[
+        freeaddrinfo(0);
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_freeaddrinfo="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_freeaddrinfo="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_freeaddrinfo" = "yes"; then
+    AC_MSG_CHECKING([if freeaddrinfo usage allowed])
+    if test "x$cares_disallow_freeaddrinfo" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_freeaddrinfo="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_freeaddrinfo="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if freeaddrinfo might be used])
+  if test "$tst_links_freeaddrinfo" = "yes" &&
+     test "$tst_proto_freeaddrinfo" = "yes" &&
+     test "$tst_compi_freeaddrinfo" = "yes" &&
+     test "$tst_allow_freeaddrinfo" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_FREEADDRINFO, 1,
+      [Define to 1 if you have the freeaddrinfo function.])
+    ac_cv_func_freeaddrinfo="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_freeaddrinfo="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_GETADDRINFO
+dnl -------------------------------------------------
+dnl Verify if getaddrinfo is available, prototyped, can
+dnl be compiled and seems to work. If all of these are
+dnl true, and usage has not been previously disallowed
+dnl with shell variable cares_disallow_getaddrinfo, then
+dnl HAVE_GETADDRINFO will be defined. Additionally when
+dnl HAVE_GETADDRINFO gets defined this will also attempt
+dnl to find out if getaddrinfo happens to be threadsafe,
+dnl defining HAVE_GETADDRINFO_THREADSAFE when true.
+
+AC_DEFUN([CARES_CHECK_FUNC_GETADDRINFO], [
+  AC_REQUIRE([CARES_INCLUDES_WS2TCPIP])dnl
+  AC_REQUIRE([CARES_INCLUDES_STDLIB])dnl
+  AC_REQUIRE([CARES_INCLUDES_STRING])dnl
+  AC_REQUIRE([CARES_INCLUDES_SYS_SOCKET])dnl
+  AC_REQUIRE([CARES_INCLUDES_NETDB])dnl
+  AC_REQUIRE([CURL_CHECK_NATIVE_WINDOWS])dnl
+  #
+  tst_links_getaddrinfo="unknown"
+  tst_proto_getaddrinfo="unknown"
+  tst_compi_getaddrinfo="unknown"
+  tst_works_getaddrinfo="unknown"
+  tst_allow_getaddrinfo="unknown"
+  tst_tsafe_getaddrinfo="unknown"
+  #
+  AC_MSG_CHECKING([if getaddrinfo can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_PROGRAM([[
+      $cares_includes_ws2tcpip
+      $cares_includes_sys_socket
+      $cares_includes_netdb
+    ]],[[
+      if(0 != getaddrinfo(0, 0, 0, 0))
+        return 1;
+    ]])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_getaddrinfo="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_getaddrinfo="no"
+  ])
+  #
+  if test "$tst_links_getaddrinfo" = "yes"; then
+    AC_MSG_CHECKING([if getaddrinfo is prototyped])
+    AC_EGREP_CPP([getaddrinfo],[
+      $cares_includes_ws2tcpip
+      $cares_includes_sys_socket
+      $cares_includes_netdb
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_getaddrinfo="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_getaddrinfo="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_getaddrinfo" = "yes"; then
+    AC_MSG_CHECKING([if getaddrinfo is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_ws2tcpip
+        $cares_includes_sys_socket
+        $cares_includes_netdb
+      ]],[[
+        if(0 != getaddrinfo(0, 0, 0, 0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_getaddrinfo="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_getaddrinfo="no"
+    ])
+  fi
+  #
+  dnl only do runtime verification when not cross-compiling
+  if test "x$cross_compiling" != "xyes" &&
+    test "$tst_compi_getaddrinfo" = "yes"; then
+    AC_MSG_CHECKING([if getaddrinfo seems to work])
+    AC_RUN_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_ws2tcpip
+        $cares_includes_stdlib
+        $cares_includes_string
+        $cares_includes_sys_socket
+        $cares_includes_netdb
+      ]],[[
+        struct addrinfo hints;
+        struct addrinfo *ai = 0;
+        int error;
+
+        memset(&hints, 0, sizeof(hints));
+        hints.ai_flags = AI_NUMERICHOST;
+        hints.ai_family = AF_UNSPEC;
+        hints.ai_socktype = SOCK_STREAM;
+        error = getaddrinfo("127.0.0.1", 0, &hints, &ai);
+        if(error || !ai)
+          exit(1); /* fail */
+        else
+          exit(0);
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_works_getaddrinfo="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_works_getaddrinfo="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_getaddrinfo" = "yes" &&
+    test "$tst_works_getaddrinfo" != "no"; then
+    AC_MSG_CHECKING([if getaddrinfo usage allowed])
+    if test "x$cares_disallow_getaddrinfo" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_getaddrinfo="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_getaddrinfo="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if getaddrinfo might be used])
+  if test "$tst_links_getaddrinfo" = "yes" &&
+     test "$tst_proto_getaddrinfo" = "yes" &&
+     test "$tst_compi_getaddrinfo" = "yes" &&
+     test "$tst_allow_getaddrinfo" = "yes" &&
+     test "$tst_works_getaddrinfo" != "no"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_GETADDRINFO, 1,
+      [Define to 1 if you have a working getaddrinfo function.])
+    ac_cv_func_getaddrinfo="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_getaddrinfo="no"
+    ac_cv_func_getaddrinfo_threadsafe="no"
+  fi
+  #
+  if test "$ac_cv_func_getaddrinfo" = "yes"; then
+    AC_MSG_CHECKING([if getaddrinfo is threadsafe])
+    case $host_os in
+      aix[[1234]].* | aix5.[[01]].*)
+        dnl aix 5.1 and older
+        tst_tsafe_getaddrinfo="no"
+        ;;
+      aix*)
+        dnl aix 5.2 and newer
+        tst_tsafe_getaddrinfo="yes"
+        ;;
+      darwin[[12345]].*)
+        dnl darwin 5.0 and mac os x 10.1.X and older
+        tst_tsafe_getaddrinfo="no"
+        ;;
+      darwin*)
+        dnl darwin 6.0 and mac os x 10.2.X and newer
+        tst_tsafe_getaddrinfo="yes"
+        ;;
+      freebsd[[1234]].* | freebsd5.[[1234]]*)
+        dnl freebsd 5.4 and older
+        tst_tsafe_getaddrinfo="no"
+        ;;
+      freebsd*)
+        dnl freebsd 5.5 and newer
+        tst_tsafe_getaddrinfo="yes"
+        ;;
+      hpux[[123456789]].* | hpux10.* | hpux11.0* | hpux11.10*)
+        dnl hpux 11.10 and older
+        tst_tsafe_getaddrinfo="no"
+        ;;
+      hpux*)
+        dnl hpux 11.11 and newer
+        tst_tsafe_getaddrinfo="yes"
+        ;;
+      netbsd[[123]].*)
+        dnl netbsd 3.X and older
+        tst_tsafe_getaddrinfo="no"
+        ;;
+      netbsd*)
+        dnl netbsd 4.X and newer
+        tst_tsafe_getaddrinfo="yes"
+        ;;
+      *bsd*)
+        dnl All other bsd's
+        tst_tsafe_getaddrinfo="no"
+        ;;
+      solaris2*)
+        dnl solaris which have it
+        tst_tsafe_getaddrinfo="yes"
+        ;;
+    esac
+    if test "$tst_tsafe_getaddrinfo" = "unknown" &&
+       test "$ac_cv_native_windows" = "yes"; then
+      tst_tsafe_getaddrinfo="yes"
+    fi
+    if test "$tst_tsafe_getaddrinfo" = "unknown"; then
+      CURL_CHECK_DEF_CC([h_errno], [
+        $cares_includes_sys_socket
+        $cares_includes_netdb
+        ], [silent])
+      if test "$curl_cv_have_def_h_errno" = "yes"; then
+        tst_h_errno_macro="yes"
+      else
+        tst_h_errno_macro="no"
+      fi
+      AC_COMPILE_IFELSE([
+        AC_LANG_PROGRAM([[
+          $cares_includes_sys_socket
+          $cares_includes_netdb
+        ]],[[
+          h_errno = 2;
+          if(0 != h_errno)
+            return 1;
+        ]])
+      ],[
+        tst_h_errno_modifiable_lvalue="yes"
+      ],[
+        tst_h_errno_modifiable_lvalue="no"
+      ])
+      AC_COMPILE_IFELSE([
+        AC_LANG_PROGRAM([[
+        ]],[[
+#if defined(_POSIX_C_SOURCE) && (_POSIX_C_SOURCE >= 200809L)
+          return 0;
+#elif defined(_XOPEN_SOURCE) && (_XOPEN_SOURCE >= 700)
+          return 0;
+#else
+          force compilation error
+#endif
+        ]])
+      ],[
+        tst_h_errno_sbs_issue_7="yes"
+      ],[
+        tst_h_errno_sbs_issue_7="no"
+      ])
+      if test "$tst_h_errno_macro" = "no" &&
+         test "$tst_h_errno_modifiable_lvalue" = "no" &&
+         test "$tst_h_errno_sbs_issue_7" = "no"; then
+        tst_tsafe_getaddrinfo="no"
+      else
+        tst_tsafe_getaddrinfo="yes"
+      fi
+    fi
+    AC_MSG_RESULT([$tst_tsafe_getaddrinfo])
+    if test "$tst_tsafe_getaddrinfo" = "yes"; then
+      AC_DEFINE_UNQUOTED(HAVE_GETADDRINFO_THREADSAFE, 1,
+        [Define to 1 if the getaddrinfo function is threadsafe.])
+      ac_cv_func_getaddrinfo_threadsafe="yes"
+    else
+      ac_cv_func_getaddrinfo_threadsafe="no"
+    fi
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_GETENV
+dnl -------------------------------------------------
+dnl Verify if getenv is available, prototyped, and
+dnl can be compiled. If all of these are true, and
+dnl usage has not been previously disallowed with
+dnl shell variable cares_disallow_getenv, then
+dnl HAVE_GETENV will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_GETENV], [
+  AC_REQUIRE([CARES_INCLUDES_STDLIB])dnl
+  #
+  tst_links_getenv="unknown"
+  tst_proto_getenv="unknown"
+  tst_compi_getenv="unknown"
+  tst_allow_getenv="unknown"
+  #
+  AC_MSG_CHECKING([if getenv can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([getenv])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_getenv="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_getenv="no"
+  ])
+  #
+  if test "$tst_links_getenv" = "yes"; then
+    AC_MSG_CHECKING([if getenv is prototyped])
+    AC_EGREP_CPP([getenv],[
+      $cares_includes_stdlib
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_getenv="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_getenv="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_getenv" = "yes"; then
+    AC_MSG_CHECKING([if getenv is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_stdlib
+      ]],[[
+        if(0 != getenv(0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_getenv="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_getenv="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_getenv" = "yes"; then
+    AC_MSG_CHECKING([if getenv usage allowed])
+    if test "x$cares_disallow_getenv" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_getenv="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_getenv="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if getenv might be used])
+  if test "$tst_links_getenv" = "yes" &&
+     test "$tst_proto_getenv" = "yes" &&
+     test "$tst_compi_getenv" = "yes" &&
+     test "$tst_allow_getenv" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_GETENV, 1,
+      [Define to 1 if you have the getenv function.])
+    ac_cv_func_getenv="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_getenv="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_GETHOSTBYADDR
+dnl -------------------------------------------------
+dnl Verify if gethostbyaddr is available, prototyped,
+dnl and can be compiled. If all of these are true,
+dnl and usage has not been previously disallowed with
+dnl shell variable cares_disallow_gethostbyaddr, then
+dnl HAVE_GETHOSTBYADDR will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_GETHOSTBYADDR], [
+  AC_REQUIRE([CARES_INCLUDES_WINSOCK2])dnl
+  AC_REQUIRE([CARES_INCLUDES_NETDB])dnl
+  #
+  tst_links_gethostbyaddr="unknown"
+  tst_proto_gethostbyaddr="unknown"
+  tst_compi_gethostbyaddr="unknown"
+  tst_allow_gethostbyaddr="unknown"
+  #
+  AC_MSG_CHECKING([if gethostbyaddr can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_PROGRAM([[
+      $cares_includes_winsock2
+      $cares_includes_netdb
+    ]],[[
+      if(0 != gethostbyaddr(0, 0, 0))
+        return 1;
+    ]])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_gethostbyaddr="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_gethostbyaddr="no"
+  ])
+  #
+  if test "$tst_links_gethostbyaddr" = "yes"; then
+    AC_MSG_CHECKING([if gethostbyaddr is prototyped])
+    AC_EGREP_CPP([gethostbyaddr],[
+      $cares_includes_winsock2
+      $cares_includes_netdb
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_gethostbyaddr="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_gethostbyaddr="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_gethostbyaddr" = "yes"; then
+    AC_MSG_CHECKING([if gethostbyaddr is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_winsock2
+        $cares_includes_netdb
+      ]],[[
+        if(0 != gethostbyaddr(0, 0, 0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_gethostbyaddr="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_gethostbyaddr="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_gethostbyaddr" = "yes"; then
+    AC_MSG_CHECKING([if gethostbyaddr usage allowed])
+    if test "x$cares_disallow_gethostbyaddr" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_gethostbyaddr="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_gethostbyaddr="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if gethostbyaddr might be used])
+  if test "$tst_links_gethostbyaddr" = "yes" &&
+     test "$tst_proto_gethostbyaddr" = "yes" &&
+     test "$tst_compi_gethostbyaddr" = "yes" &&
+     test "$tst_allow_gethostbyaddr" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_GETHOSTBYADDR, 1,
+      [Define to 1 if you have the gethostbyaddr function.])
+    ac_cv_func_gethostbyaddr="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_gethostbyaddr="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_GETHOSTBYNAME
+dnl -------------------------------------------------
+dnl Verify if gethostbyname is available, prototyped,
+dnl and can be compiled. If all of these are true,
+dnl and usage has not been previously disallowed with
+dnl shell variable cares_disallow_gethostbyname, then
+dnl HAVE_GETHOSTBYNAME will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_GETHOSTBYNAME], [
+  AC_REQUIRE([CARES_INCLUDES_WINSOCK2])dnl
+  AC_REQUIRE([CARES_INCLUDES_NETDB])dnl
+  #
+  tst_links_gethostbyname="unknown"
+  tst_proto_gethostbyname="unknown"
+  tst_compi_gethostbyname="unknown"
+  tst_allow_gethostbyname="unknown"
+  #
+  AC_MSG_CHECKING([if gethostbyname can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_PROGRAM([[
+      $cares_includes_winsock2
+      $cares_includes_netdb
+    ]],[[
+      if(0 != gethostbyname(0))
+        return 1;
+    ]])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_gethostbyname="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_gethostbyname="no"
+  ])
+  #
+  if test "$tst_links_gethostbyname" = "yes"; then
+    AC_MSG_CHECKING([if gethostbyname is prototyped])
+    AC_EGREP_CPP([gethostbyname],[
+      $cares_includes_winsock2
+      $cares_includes_netdb
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_gethostbyname="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_gethostbyname="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_gethostbyname" = "yes"; then
+    AC_MSG_CHECKING([if gethostbyname is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_winsock2
+        $cares_includes_netdb
+      ]],[[
+        if(0 != gethostbyname(0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_gethostbyname="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_gethostbyname="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_gethostbyname" = "yes"; then
+    AC_MSG_CHECKING([if gethostbyname usage allowed])
+    if test "x$cares_disallow_gethostbyname" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_gethostbyname="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_gethostbyname="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if gethostbyname might be used])
+  if test "$tst_links_gethostbyname" = "yes" &&
+     test "$tst_proto_gethostbyname" = "yes" &&
+     test "$tst_compi_gethostbyname" = "yes" &&
+     test "$tst_allow_gethostbyname" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_GETHOSTBYNAME, 1,
+      [Define to 1 if you have the gethostbyname function.])
+    ac_cv_func_gethostbyname="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_gethostbyname="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_GETHOSTNAME
+dnl -------------------------------------------------
+dnl Verify if gethostname is available, prototyped, and
+dnl can be compiled. If all of these are true, and
+dnl usage has not been previously disallowed with
+dnl shell variable cares_disallow_gethostname, then
+dnl HAVE_GETHOSTNAME will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_GETHOSTNAME], [
+  AC_REQUIRE([CARES_INCLUDES_WINSOCK2])dnl
+  AC_REQUIRE([CARES_INCLUDES_UNISTD])dnl
+  AC_REQUIRE([CARES_PREPROCESS_CALLCONV])dnl
+  #
+  tst_links_gethostname="unknown"
+  tst_proto_gethostname="unknown"
+  tst_compi_gethostname="unknown"
+  tst_allow_gethostname="unknown"
+  #
+  AC_MSG_CHECKING([if gethostname can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_PROGRAM([[
+      $cares_includes_winsock2
+      $cares_includes_unistd
+    ]],[[
+      if(0 != gethostname(0, 0))
+        return 1;
+    ]])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_gethostname="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_gethostname="no"
+  ])
+  #
+  if test "$tst_links_gethostname" = "yes"; then
+    AC_MSG_CHECKING([if gethostname is prototyped])
+    AC_EGREP_CPP([gethostname],[
+      $cares_includes_winsock2
+      $cares_includes_unistd
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_gethostname="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_gethostname="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_gethostname" = "yes"; then
+    AC_MSG_CHECKING([if gethostname is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_winsock2
+        $cares_includes_unistd
+      ]],[[
+        if(0 != gethostname(0, 0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_gethostname="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_gethostname="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_gethostname" = "yes"; then
+    AC_MSG_CHECKING([for gethostname arg 2 data type])
+    tst_gethostname_type_arg2="unknown"
+    for tst_arg1 in 'char *' 'unsigned char *' 'void *'; do
+      for tst_arg2 in 'int' 'unsigned int' 'size_t'; do
+        if test "$tst_gethostname_type_arg2" = "unknown"; then
+          AC_COMPILE_IFELSE([
+            AC_LANG_PROGRAM([[
+              $cares_includes_winsock2
+              $cares_includes_unistd
+              $cares_preprocess_callconv
+              extern int FUNCALLCONV gethostname($tst_arg1, $tst_arg2);
+            ]],[[
+              if(0 != gethostname(0, 0))
+                return 1;
+            ]])
+          ],[
+            tst_gethostname_type_arg2="$tst_arg2"
+          ])
+        fi
+      done
+    done
+    AC_MSG_RESULT([$tst_gethostname_type_arg2])
+    if test "$tst_gethostname_type_arg2" != "unknown"; then
+      AC_DEFINE_UNQUOTED(GETHOSTNAME_TYPE_ARG2, $tst_gethostname_type_arg2,
+        [Define to the type of arg 2 for gethostname.])
+    fi
+  fi
+  #
+  if test "$tst_compi_gethostname" = "yes"; then
+    AC_MSG_CHECKING([if gethostname usage allowed])
+    if test "x$cares_disallow_gethostname" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_gethostname="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_gethostname="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if gethostname might be used])
+  if test "$tst_links_gethostname" = "yes" &&
+     test "$tst_proto_gethostname" = "yes" &&
+     test "$tst_compi_gethostname" = "yes" &&
+     test "$tst_allow_gethostname" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_GETHOSTNAME, 1,
+      [Define to 1 if you have the gethostname function.])
+    ac_cv_func_gethostname="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_gethostname="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_GETSERVBYPORT_R
+dnl -------------------------------------------------
+dnl Verify if getservbyport_r is available, prototyped,
+dnl and can be compiled. If all of these are true, and
+dnl usage has not been previously disallowed with
+dnl shell variable cares_disallow_getservbyport_r, then
+dnl HAVE_GETSERVBYPORT_R will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_GETSERVBYPORT_R], [
+  AC_REQUIRE([CARES_INCLUDES_NETDB])dnl
+  #
+  tst_links_getservbyport_r="unknown"
+  tst_proto_getservbyport_r="unknown"
+  tst_compi_getservbyport_r="unknown"
+  tst_allow_getservbyport_r="unknown"
+  tst_nargs_getservbyport_r="unknown"
+  #
+  AC_MSG_CHECKING([if getservbyport_r can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([getservbyport_r])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_getservbyport_r="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_getservbyport_r="no"
+  ])
+  #
+  if test "$tst_links_getservbyport_r" = "yes"; then
+    AC_MSG_CHECKING([if getservbyport_r is prototyped])
+    AC_EGREP_CPP([getservbyport_r],[
+      $cares_includes_netdb
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_getservbyport_r="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_getservbyport_r="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_getservbyport_r" = "yes"; then
+    if test "$tst_nargs_getservbyport_r" = "unknown"; then
+      AC_MSG_CHECKING([if getservbyport_r takes 4 args.])
+      AC_COMPILE_IFELSE([
+        AC_LANG_PROGRAM([[
+          $cares_includes_netdb
+        ]],[[
+          if(0 != getservbyport_r(0, 0, 0, 0))
+            return 1;
+        ]])
+      ],[
+        AC_MSG_RESULT([yes])
+        tst_compi_getservbyport_r="yes"
+        tst_nargs_getservbyport_r="4"
+      ],[
+        AC_MSG_RESULT([no])
+        tst_compi_getservbyport_r="no"
+      ])
+    fi
+    if test "$tst_nargs_getservbyport_r" = "unknown"; then
+      AC_MSG_CHECKING([if getservbyport_r takes 5 args.])
+      AC_COMPILE_IFELSE([
+        AC_LANG_PROGRAM([[
+          $cares_includes_netdb
+        ]],[[
+          if(0 != getservbyport_r(0, 0, 0, 0, 0))
+            return 1;
+        ]])
+      ],[
+        AC_MSG_RESULT([yes])
+        tst_compi_getservbyport_r="yes"
+        tst_nargs_getservbyport_r="5"
+      ],[
+        AC_MSG_RESULT([no])
+        tst_compi_getservbyport_r="no"
+      ])
+    fi
+    if test "$tst_nargs_getservbyport_r" = "unknown"; then
+      AC_MSG_CHECKING([if getservbyport_r takes 6 args.])
+      AC_COMPILE_IFELSE([
+        AC_LANG_PROGRAM([[
+          $cares_includes_netdb
+        ]],[[
+          if(0 != getservbyport_r(0, 0, 0, 0, 0, 0))
+            return 1;
+        ]])
+      ],[
+        AC_MSG_RESULT([yes])
+        tst_compi_getservbyport_r="yes"
+        tst_nargs_getservbyport_r="6"
+      ],[
+        AC_MSG_RESULT([no])
+        tst_compi_getservbyport_r="no"
+      ])
+    fi
+    AC_MSG_CHECKING([if getservbyport_r is compilable])
+    if test "$tst_compi_getservbyport_r" = "yes"; then
+      AC_MSG_RESULT([yes])
+    else
+      AC_MSG_RESULT([no])
+    fi
+  fi
+  #
+  if test "$tst_compi_getservbyport_r" = "yes"; then
+    AC_MSG_CHECKING([if getservbyport_r usage allowed])
+    if test "x$cares_disallow_getservbyport_r" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_getservbyport_r="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_getservbyport_r="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if getservbyport_r might be used])
+  if test "$tst_links_getservbyport_r" = "yes" &&
+     test "$tst_proto_getservbyport_r" = "yes" &&
+     test "$tst_compi_getservbyport_r" = "yes" &&
+     test "$tst_allow_getservbyport_r" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_GETSERVBYPORT_R, 1,
+      [Define to 1 if you have the getservbyport_r function.])
+    AC_DEFINE_UNQUOTED(GETSERVBYPORT_R_ARGS, $tst_nargs_getservbyport_r,
+      [Specifies the number of arguments to getservbyport_r])
+    if test "$tst_nargs_getservbyport_r" -eq "4"; then
+      AC_DEFINE(GETSERVBYPORT_R_BUFSIZE, sizeof(struct servent_data),
+        [Specifies the size of the buffer to pass to getservbyport_r])
+    else
+      AC_DEFINE(GETSERVBYPORT_R_BUFSIZE, 4096,
+        [Specifies the size of the buffer to pass to getservbyport_r])
+    fi
+    ac_cv_func_getservbyport_r="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_getservbyport_r="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_INET_NET_PTON
+dnl -------------------------------------------------
+dnl Verify if inet_net_pton is available, prototyped, can
+dnl be compiled and seems to work. If all of these are
+dnl true, and usage has not been previously disallowed
+dnl with shell variable cares_disallow_inet_net_pton, then
+dnl HAVE_INET_NET_PTON will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_INET_NET_PTON], [
+  AC_REQUIRE([CARES_INCLUDES_STDLIB])dnl
+  AC_REQUIRE([CARES_INCLUDES_ARPA_INET])dnl
+  AC_REQUIRE([CARES_INCLUDES_STRING])dnl
+  #
+  tst_links_inet_net_pton="unknown"
+  tst_proto_inet_net_pton="unknown"
+  tst_compi_inet_net_pton="unknown"
+  tst_works_inet_net_pton="unknown"
+  tst_allow_inet_net_pton="unknown"
+  #
+  AC_MSG_CHECKING([if inet_net_pton can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([inet_net_pton])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_inet_net_pton="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_inet_net_pton="no"
+  ])
+  #
+  if test "$tst_links_inet_net_pton" = "yes"; then
+    AC_MSG_CHECKING([if inet_net_pton is prototyped])
+    AC_EGREP_CPP([inet_net_pton],[
+      $cares_includes_arpa_inet
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_inet_net_pton="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_inet_net_pton="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_inet_net_pton" = "yes"; then
+    AC_MSG_CHECKING([if inet_net_pton is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_arpa_inet
+      ]],[[
+        if(0 != inet_net_pton(0, 0, 0, 0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_inet_net_pton="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_inet_net_pton="no"
+    ])
+  fi
+  #
+  dnl only do runtime verification when not cross-compiling
+  if test "x$cross_compiling" != "xyes" &&
+    test "$tst_compi_inet_net_pton" = "yes"; then
+    AC_MSG_CHECKING([if inet_net_pton seems to work])
+    AC_RUN_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_stdlib
+        $cares_includes_arpa_inet
+        $cares_includes_string
+      ]],[[
+        unsigned char ipv6a[16+1];
+        unsigned char ipv4a[4+1];
+        const char *ipv6net1 = "fe80::214:4fff:fe0b:76c8";
+        const char *ipv6net2 = "::fffe:7f00:1";
+        const char *ipv6net3 = "7f20:1::/64";
+        const char *ipv6net4 = "7f20:1::/2147483649";
+        const char *ipv4net1 = "192.168.100.1";
+        const char *ipv4net2 = "192.168.100/32";
+        const char *ipv4net3 = "192.168.100.1/2147483649";
+        /* - */
+        memset(ipv4a, 1, sizeof(ipv4a));
+        if(32 != inet_net_pton(AF_INET, ipv4net1, ipv4a, 4))
+          exit(1); /* fail */
+        /* - */
+        if( (ipv4a[0x00] != 0xc0) ||
+            (ipv4a[0x01] != 0xa8) ||
+            (ipv4a[0x02] != 0x64) ||
+            (ipv4a[0x03] != 0x01) ||
+            (ipv4a[0x04] != 0x01) )
+          exit(1); /* fail */
+        /* - */
+        memset(ipv4a, 1, sizeof(ipv4a));
+        if(32 != inet_net_pton(AF_INET, ipv4net2, ipv4a, 4))
+          exit(1); /* fail */
+        /* - */
+        if( (ipv4a[0x00] != 0xc0) ||
+            (ipv4a[0x01] != 0xa8) ||
+            (ipv4a[0x02] != 0x64) ||
+            (ipv4a[0x03] != 0x00) ||
+            (ipv4a[0x04] != 0x01) )
+          exit(1); /* fail */
+        /* - */
+        memset(ipv4a, 1, sizeof(ipv4a));
+        if(-1 != inet_net_pton(AF_INET, ipv4net3, ipv4a, 4))
+          exit(1); /* fail */
+        /* - */
+        memset(ipv6a, 1, sizeof(ipv6a));
+        if(128 != inet_net_pton(AF_INET6, ipv6net1, ipv6a, 16))
+          exit(1); /* fail */
+        /* - */
+        if( (ipv6a[0x00] != 0xfe) ||
+            (ipv6a[0x01] != 0x80) ||
+            (ipv6a[0x08] != 0x02) ||
+            (ipv6a[0x09] != 0x14) ||
+            (ipv6a[0x0a] != 0x4f) ||
+            (ipv6a[0x0b] != 0xff) ||
+            (ipv6a[0x0c] != 0xfe) ||
+            (ipv6a[0x0d] != 0x0b) ||
+            (ipv6a[0x0e] != 0x76) ||
+            (ipv6a[0x0f] != 0xc8) ||
+            (ipv6a[0x10] != 0x01) )
+          exit(1); /* fail */
+        /* - */
+        if( (ipv6a[0x02] != 0x0) ||
+            (ipv6a[0x03] != 0x0) ||
+            (ipv6a[0x04] != 0x0) ||
+            (ipv6a[0x05] != 0x0) ||
+            (ipv6a[0x06] != 0x0) ||
+            (ipv6a[0x07] != 0x0) )
+          exit(1); /* fail */
+        /* - */
+        memset(ipv6a, 0, sizeof(ipv6a));
+        ipv6a[0x10] = 0x01;
+        if(128 != inet_net_pton(AF_INET6, ipv6net2, ipv6a, 16))
+          exit(1); /* fail */
+        /* - */
+        if( (ipv6a[0x0a] != 0xff) ||
+            (ipv6a[0x0b] != 0xfe) ||
+            (ipv6a[0x0c] != 0x7f) ||
+            (ipv6a[0x0f] != 0x01) ||
+            (ipv6a[0x10] != 0x01) )
+          exit(1); /* fail */
+        /* - */
+        if( (ipv6a[0x00] != 0x0) ||
+            (ipv6a[0x01] != 0x0) ||
+            (ipv6a[0x02] != 0x0) ||
+            (ipv6a[0x03] != 0x0) ||
+            (ipv6a[0x04] != 0x0) ||
+            (ipv6a[0x05] != 0x0) ||
+            (ipv6a[0x06] != 0x0) ||
+            (ipv6a[0x07] != 0x0) ||
+            (ipv6a[0x08] != 0x0) ||
+            (ipv6a[0x09] != 0x0) ||
+            (ipv6a[0x0d] != 0x0) ||
+            (ipv6a[0x0e] != 0x0) )
+          exit(1); /* fail */
+        /* - */
+        memset(ipv6a, 1, sizeof(ipv6a));
+        if(64 != inet_net_pton(AF_INET6, ipv6net3, ipv6a, 16))
+          exit(1); /* fail */
+        if( (ipv6a[0x00] != 0x7f) ||
+            (ipv6a[0x01] != 0x20) ||
+            (ipv6a[0x03] != 0x01) ||
+            (ipv6a[0x08] != 0x01) ||
+            (ipv6a[0x09] != 0x01) ||
+            (ipv6a[0x0a] != 0x01) ||
+            (ipv6a[0x0b] != 0x01) ||
+            (ipv6a[0x0c] != 0x01) ||
+            (ipv6a[0x0d] != 0x01) ||
+            (ipv6a[0x0e] != 0x01) ||
+            (ipv6a[0x0f] != 0x01) ||
+            (ipv6a[0x10] != 0x01) )
+          exit(1); /* fail */
+        if( (ipv6a[0x02] != 0x0) ||
+            (ipv6a[0x04] != 0x0) ||
+            (ipv6a[0x05] != 0x0) ||
+            (ipv6a[0x06] != 0x0) ||
+            (ipv6a[0x07] != 0x0) ||
+            (ipv6a[0x07] != 0x0) )
+          exit(1); /* fail */
+        /* - */
+        memset(ipv6a, 1, sizeof(ipv6a));
+        if(-1 != inet_net_pton(AF_INET6, ipv6net4, ipv6a, 16))
+          exit(1); /* fail */
+        /* - */
+        exit(0);
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_works_inet_net_pton="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_works_inet_net_pton="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_inet_net_pton" = "yes" &&
+    test "$tst_works_inet_net_pton" != "no"; then
+    AC_MSG_CHECKING([if inet_net_pton usage allowed])
+    if test "x$cares_disallow_inet_net_pton" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_inet_net_pton="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_inet_net_pton="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if inet_net_pton might be used])
+  if test "$tst_links_inet_net_pton" = "yes" &&
+     test "$tst_proto_inet_net_pton" = "yes" &&
+     test "$tst_compi_inet_net_pton" = "yes" &&
+     test "$tst_allow_inet_net_pton" = "yes" &&
+     test "$tst_works_inet_net_pton" != "no"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_INET_NET_PTON, 1,
+      [Define to 1 if you have a IPv6 capable working inet_net_pton function.])
+    ac_cv_func_inet_net_pton="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_inet_net_pton="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_INET_NTOP
+dnl -------------------------------------------------
+dnl Verify if inet_ntop is available, prototyped, can
+dnl be compiled and seems to work. If all of these are
+dnl true, and usage has not been previously disallowed
+dnl with shell variable cares_disallow_inet_ntop, then
+dnl HAVE_INET_NTOP will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_INET_NTOP], [
+  AC_REQUIRE([CARES_INCLUDES_STDLIB])dnl
+  AC_REQUIRE([CARES_INCLUDES_ARPA_INET])dnl
+  AC_REQUIRE([CARES_INCLUDES_STRING])dnl
+  #
+  tst_links_inet_ntop="unknown"
+  tst_proto_inet_ntop="unknown"
+  tst_compi_inet_ntop="unknown"
+  tst_works_inet_ntop="unknown"
+  tst_allow_inet_ntop="unknown"
+  #
+  AC_MSG_CHECKING([if inet_ntop can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([inet_ntop])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_inet_ntop="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_inet_ntop="no"
+  ])
+  #
+  if test "$tst_links_inet_ntop" = "yes"; then
+    AC_MSG_CHECKING([if inet_ntop is prototyped])
+    AC_EGREP_CPP([inet_ntop],[
+      $cares_includes_arpa_inet
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_inet_ntop="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_inet_ntop="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_inet_ntop" = "yes"; then
+    AC_MSG_CHECKING([if inet_ntop is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_arpa_inet
+      ]],[[
+        if(0 != inet_ntop(0, 0, 0, 0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_inet_ntop="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_inet_ntop="no"
+    ])
+  fi
+  #
+  dnl only do runtime verification when not cross-compiling
+  if test "x$cross_compiling" != "xyes" &&
+    test "$tst_compi_inet_ntop" = "yes"; then
+    AC_MSG_CHECKING([if inet_ntop seems to work])
+    AC_RUN_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_stdlib
+        $cares_includes_arpa_inet
+        $cares_includes_string
+      ]],[[
+        char ipv6res[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")];
+        char ipv4res[sizeof "255.255.255.255"];
+        unsigned char ipv6a[26];
+        unsigned char ipv4a[5];
+        char *ipv6ptr = 0;
+        char *ipv4ptr = 0;
+        /* - */
+        ipv4res[0] = '\0';
+        ipv4a[0] = 0xc0;
+        ipv4a[1] = 0xa8;
+        ipv4a[2] = 0x64;
+        ipv4a[3] = 0x01;
+        ipv4a[4] = 0x01;
+        /* - */
+        ipv4ptr = inet_ntop(AF_INET, ipv4a, ipv4res, sizeof(ipv4res));
+        if(!ipv4ptr)
+          exit(1); /* fail */
+        if(ipv4ptr != ipv4res)
+          exit(1); /* fail */
+        if(!ipv4ptr[0])
+          exit(1); /* fail */
+        if(memcmp(ipv4res, "192.168.100.1", 13) != 0)
+          exit(1); /* fail */
+        /* - */
+        ipv6res[0] = '\0';
+        memset(ipv6a, 0, sizeof(ipv6a));
+        ipv6a[0] = 0xfe;
+        ipv6a[1] = 0x80;
+        ipv6a[8] = 0x02;
+        ipv6a[9] = 0x14;
+        ipv6a[10] = 0x4f;
+        ipv6a[11] = 0xff;
+        ipv6a[12] = 0xfe;
+        ipv6a[13] = 0x0b;
+        ipv6a[14] = 0x76;
+        ipv6a[15] = 0xc8;
+        ipv6a[25] = 0x01;
+        /* - */
+        ipv6ptr = inet_ntop(AF_INET6, ipv6a, ipv6res, sizeof(ipv6res));
+        if(!ipv6ptr)
+          exit(1); /* fail */
+        if(ipv6ptr != ipv6res)
+          exit(1); /* fail */
+        if(!ipv6ptr[0])
+          exit(1); /* fail */
+        if(memcmp(ipv6res, "fe80::214:4fff:fe0b:76c8", 24) != 0)
+          exit(1); /* fail */
+        /* - */
+        exit(0);
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_works_inet_ntop="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_works_inet_ntop="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_inet_ntop" = "yes" &&
+    test "$tst_works_inet_ntop" != "no"; then
+    AC_MSG_CHECKING([if inet_ntop usage allowed])
+    if test "x$cares_disallow_inet_ntop" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_inet_ntop="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_inet_ntop="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if inet_ntop might be used])
+  if test "$tst_links_inet_ntop" = "yes" &&
+     test "$tst_proto_inet_ntop" = "yes" &&
+     test "$tst_compi_inet_ntop" = "yes" &&
+     test "$tst_allow_inet_ntop" = "yes" &&
+     test "$tst_works_inet_ntop" != "no"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_INET_NTOP, 1,
+      [Define to 1 if you have a IPv6 capable working inet_ntop function.])
+    ac_cv_func_inet_ntop="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_inet_ntop="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_INET_PTON
+dnl -------------------------------------------------
+dnl Verify if inet_pton is available, prototyped, can
+dnl be compiled and seems to work. If all of these are
+dnl true, and usage has not been previously disallowed
+dnl with shell variable cares_disallow_inet_pton, then
+dnl HAVE_INET_PTON will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_INET_PTON], [
+  AC_REQUIRE([CARES_INCLUDES_STDLIB])dnl
+  AC_REQUIRE([CARES_INCLUDES_ARPA_INET])dnl
+  AC_REQUIRE([CARES_INCLUDES_STRING])dnl
+  #
+  tst_links_inet_pton="unknown"
+  tst_proto_inet_pton="unknown"
+  tst_compi_inet_pton="unknown"
+  tst_works_inet_pton="unknown"
+  tst_allow_inet_pton="unknown"
+  #
+  AC_MSG_CHECKING([if inet_pton can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([inet_pton])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_inet_pton="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_inet_pton="no"
+  ])
+  #
+  if test "$tst_links_inet_pton" = "yes"; then
+    AC_MSG_CHECKING([if inet_pton is prototyped])
+    AC_EGREP_CPP([inet_pton],[
+      $cares_includes_arpa_inet
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_inet_pton="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_inet_pton="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_inet_pton" = "yes"; then
+    AC_MSG_CHECKING([if inet_pton is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_arpa_inet
+      ]],[[
+        if(0 != inet_pton(0, 0, 0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_inet_pton="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_inet_pton="no"
+    ])
+  fi
+  #
+  dnl only do runtime verification when not cross-compiling
+  if test "x$cross_compiling" != "xyes" &&
+    test "$tst_compi_inet_pton" = "yes"; then
+    AC_MSG_CHECKING([if inet_pton seems to work])
+    AC_RUN_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_stdlib
+        $cares_includes_arpa_inet
+        $cares_includes_string
+      ]],[[
+        unsigned char ipv6a[16+1];
+        unsigned char ipv4a[4+1];
+        const char *ipv6src = "fe80::214:4fff:fe0b:76c8";
+        const char *ipv4src = "192.168.100.1";
+        /* - */
+        memset(ipv4a, 1, sizeof(ipv4a));
+        if(1 != inet_pton(AF_INET, ipv4src, ipv4a))
+          exit(1); /* fail */
+        /* - */
+        if( (ipv4a[0] != 0xc0) ||
+            (ipv4a[1] != 0xa8) ||
+            (ipv4a[2] != 0x64) ||
+            (ipv4a[3] != 0x01) ||
+            (ipv4a[4] != 0x01) )
+          exit(1); /* fail */
+        /* - */
+        memset(ipv6a, 1, sizeof(ipv6a));
+        if(1 != inet_pton(AF_INET6, ipv6src, ipv6a))
+          exit(1); /* fail */
+        /* - */
+        if( (ipv6a[0]  != 0xfe) ||
+            (ipv6a[1]  != 0x80) ||
+            (ipv6a[8]  != 0x02) ||
+            (ipv6a[9]  != 0x14) ||
+            (ipv6a[10] != 0x4f) ||
+            (ipv6a[11] != 0xff) ||
+            (ipv6a[12] != 0xfe) ||
+            (ipv6a[13] != 0x0b) ||
+            (ipv6a[14] != 0x76) ||
+            (ipv6a[15] != 0xc8) ||
+            (ipv6a[16] != 0x01) )
+          exit(1); /* fail */
+        /* - */
+        if( (ipv6a[2]  != 0x0) ||
+            (ipv6a[3]  != 0x0) ||
+            (ipv6a[4]  != 0x0) ||
+            (ipv6a[5]  != 0x0) ||
+            (ipv6a[6]  != 0x0) ||
+            (ipv6a[7]  != 0x0) )
+          exit(1); /* fail */
+        /* - */
+        exit(0);
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_works_inet_pton="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_works_inet_pton="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_inet_pton" = "yes" &&
+    test "$tst_works_inet_pton" != "no"; then
+    AC_MSG_CHECKING([if inet_pton usage allowed])
+    if test "x$cares_disallow_inet_pton" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_inet_pton="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_inet_pton="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if inet_pton might be used])
+  if test "$tst_links_inet_pton" = "yes" &&
+     test "$tst_proto_inet_pton" = "yes" &&
+     test "$tst_compi_inet_pton" = "yes" &&
+     test "$tst_allow_inet_pton" = "yes" &&
+     test "$tst_works_inet_pton" != "no"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_INET_PTON, 1,
+      [Define to 1 if you have a IPv6 capable working inet_pton function.])
+    ac_cv_func_inet_pton="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_inet_pton="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_IOCTL
+dnl -------------------------------------------------
+dnl Verify if ioctl is available, prototyped, and
+dnl can be compiled. If all of these are true, and
+dnl usage has not been previously disallowed with
+dnl shell variable cares_disallow_ioctl, then
+dnl HAVE_IOCTL will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_IOCTL], [
+  AC_REQUIRE([CARES_INCLUDES_STROPTS])dnl
+  #
+  tst_links_ioctl="unknown"
+  tst_proto_ioctl="unknown"
+  tst_compi_ioctl="unknown"
+  tst_allow_ioctl="unknown"
+  #
+  AC_MSG_CHECKING([if ioctl can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([ioctl])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_ioctl="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_ioctl="no"
+  ])
+  #
+  if test "$tst_links_ioctl" = "yes"; then
+    AC_MSG_CHECKING([if ioctl is prototyped])
+    AC_EGREP_CPP([ioctl],[
+      $cares_includes_stropts
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_ioctl="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_ioctl="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_ioctl" = "yes"; then
+    AC_MSG_CHECKING([if ioctl is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_stropts
+      ]],[[
+        if(0 != ioctl(0, 0, 0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_ioctl="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_ioctl="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_ioctl" = "yes"; then
+    AC_MSG_CHECKING([if ioctl usage allowed])
+    if test "x$cares_disallow_ioctl" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_ioctl="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_ioctl="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if ioctl might be used])
+  if test "$tst_links_ioctl" = "yes" &&
+     test "$tst_proto_ioctl" = "yes" &&
+     test "$tst_compi_ioctl" = "yes" &&
+     test "$tst_allow_ioctl" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_IOCTL, 1,
+      [Define to 1 if you have the ioctl function.])
+    ac_cv_func_ioctl="yes"
+    CARES_CHECK_FUNC_IOCTL_FIONBIO
+    CARES_CHECK_FUNC_IOCTL_SIOCGIFADDR
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_ioctl="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_IOCTL_FIONBIO
+dnl -------------------------------------------------
+dnl Verify if ioctl with the FIONBIO command is
+dnl available, can be compiled, and seems to work. If
+dnl all of these are true, then HAVE_IOCTL_FIONBIO
+dnl will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_IOCTL_FIONBIO], [
+  #
+  tst_compi_ioctl_fionbio="unknown"
+  tst_allow_ioctl_fionbio="unknown"
+  #
+  if test "$ac_cv_func_ioctl" = "yes"; then
+    AC_MSG_CHECKING([if ioctl FIONBIO is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_stropts
+      ]],[[
+        int flags = 0;
+        if(0 != ioctl(0, FIONBIO, &flags))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_ioctl_fionbio="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_ioctl_fionbio="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_ioctl_fionbio" = "yes"; then
+    AC_MSG_CHECKING([if ioctl FIONBIO usage allowed])
+    if test "x$cares_disallow_ioctl_fionbio" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_ioctl_fionbio="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_ioctl_fionbio="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if ioctl FIONBIO might be used])
+  if test "$tst_compi_ioctl_fionbio" = "yes" &&
+     test "$tst_allow_ioctl_fionbio" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_IOCTL_FIONBIO, 1,
+      [Define to 1 if you have a working ioctl FIONBIO function.])
+    ac_cv_func_ioctl_fionbio="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_ioctl_fionbio="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_IOCTL_SIOCGIFADDR
+dnl -------------------------------------------------
+dnl Verify if ioctl with the SIOCGIFADDR command is available,
+dnl struct ifreq is defined, they can be compiled, and seem to
+dnl work. If all of these are true, then HAVE_IOCTL_SIOCGIFADDR
+dnl will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_IOCTL_SIOCGIFADDR], [
+  #
+  tst_compi_ioctl_siocgifaddr="unknown"
+  tst_allow_ioctl_siocgifaddr="unknown"
+  #
+  if test "$ac_cv_func_ioctl" = "yes"; then
+    AC_MSG_CHECKING([if ioctl SIOCGIFADDR is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_stropts
+        #include <net/if.h>
+      ]],[[
+        struct ifreq ifr;
+        if(0 != ioctl(0, SIOCGIFADDR, &ifr))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_ioctl_siocgifaddr="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_ioctl_siocgifaddr="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_ioctl_siocgifaddr" = "yes"; then
+    AC_MSG_CHECKING([if ioctl SIOCGIFADDR usage allowed])
+    if test "x$cares_disallow_ioctl_siocgifaddr" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_ioctl_siocgifaddr="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_ioctl_siocgifaddr="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if ioctl SIOCGIFADDR might be used])
+  if test "$tst_compi_ioctl_siocgifaddr" = "yes" &&
+     test "$tst_allow_ioctl_siocgifaddr" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_IOCTL_SIOCGIFADDR, 1,
+      [Define to 1 if you have a working ioctl SIOCGIFADDR function.])
+    ac_cv_func_ioctl_siocgifaddr="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_ioctl_siocgifaddr="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_IOCTLSOCKET
+dnl -------------------------------------------------
+dnl Verify if ioctlsocket is available, prototyped, and
+dnl can be compiled. If all of these are true, and
+dnl usage has not been previously disallowed with
+dnl shell variable cares_disallow_ioctlsocket, then
+dnl HAVE_IOCTLSOCKET will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_IOCTLSOCKET], [
+  AC_REQUIRE([CARES_INCLUDES_WINSOCK2])dnl
+  #
+  tst_links_ioctlsocket="unknown"
+  tst_proto_ioctlsocket="unknown"
+  tst_compi_ioctlsocket="unknown"
+  tst_allow_ioctlsocket="unknown"
+  #
+  AC_MSG_CHECKING([if ioctlsocket can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_PROGRAM([[
+      $cares_includes_winsock2
+    ]],[[
+      if(0 != ioctlsocket(0, 0, 0))
+        return 1;
+    ]])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_ioctlsocket="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_ioctlsocket="no"
+  ])
+  #
+  if test "$tst_links_ioctlsocket" = "yes"; then
+    AC_MSG_CHECKING([if ioctlsocket is prototyped])
+    AC_EGREP_CPP([ioctlsocket],[
+      $cares_includes_winsock2
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_ioctlsocket="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_ioctlsocket="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_ioctlsocket" = "yes"; then
+    AC_MSG_CHECKING([if ioctlsocket is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_winsock2
+      ]],[[
+        if(0 != ioctlsocket(0, 0, 0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_ioctlsocket="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_ioctlsocket="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_ioctlsocket" = "yes"; then
+    AC_MSG_CHECKING([if ioctlsocket usage allowed])
+    if test "x$cares_disallow_ioctlsocket" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_ioctlsocket="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_ioctlsocket="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if ioctlsocket might be used])
+  if test "$tst_links_ioctlsocket" = "yes" &&
+     test "$tst_proto_ioctlsocket" = "yes" &&
+     test "$tst_compi_ioctlsocket" = "yes" &&
+     test "$tst_allow_ioctlsocket" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_IOCTLSOCKET, 1,
+      [Define to 1 if you have the ioctlsocket function.])
+    ac_cv_func_ioctlsocket="yes"
+    CARES_CHECK_FUNC_IOCTLSOCKET_FIONBIO
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_ioctlsocket="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_IOCTLSOCKET_FIONBIO
+dnl -------------------------------------------------
+dnl Verify if ioctlsocket with the FIONBIO command is
+dnl available, can be compiled, and seems to work. If
+dnl all of these are true, then HAVE_IOCTLSOCKET_FIONBIO
+dnl will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_IOCTLSOCKET_FIONBIO], [
+  #
+  tst_compi_ioctlsocket_fionbio="unknown"
+  tst_allow_ioctlsocket_fionbio="unknown"
+  #
+  if test "$ac_cv_func_ioctlsocket" = "yes"; then
+    AC_MSG_CHECKING([if ioctlsocket FIONBIO is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_winsock2
+      ]],[[
+        int flags = 0;
+        if(0 != ioctlsocket(0, FIONBIO, &flags))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_ioctlsocket_fionbio="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_ioctlsocket_fionbio="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_ioctlsocket_fionbio" = "yes"; then
+    AC_MSG_CHECKING([if ioctlsocket FIONBIO usage allowed])
+    if test "x$cares_disallow_ioctlsocket_fionbio" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_ioctlsocket_fionbio="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_ioctlsocket_fionbio="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if ioctlsocket FIONBIO might be used])
+  if test "$tst_compi_ioctlsocket_fionbio" = "yes" &&
+     test "$tst_allow_ioctlsocket_fionbio" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_IOCTLSOCKET_FIONBIO, 1,
+      [Define to 1 if you have a working ioctlsocket FIONBIO function.])
+    ac_cv_func_ioctlsocket_fionbio="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_ioctlsocket_fionbio="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_IOCTLSOCKET_CAMEL
+dnl -------------------------------------------------
+dnl Verify if IoctlSocket is available, prototyped, and
+dnl can be compiled. If all of these are true, and
+dnl usage has not been previously disallowed with
+dnl shell variable cares_disallow_ioctlsocket_camel,
+dnl then HAVE_IOCTLSOCKET_CAMEL will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_IOCTLSOCKET_CAMEL], [
+  AC_REQUIRE([CARES_INCLUDES_STROPTS])dnl
+  #
+  tst_links_ioctlsocket_camel="unknown"
+  tst_proto_ioctlsocket_camel="unknown"
+  tst_compi_ioctlsocket_camel="unknown"
+  tst_allow_ioctlsocket_camel="unknown"
+  #
+  AC_MSG_CHECKING([if IoctlSocket can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([IoctlSocket])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_ioctlsocket_camel="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_ioctlsocket_camel="no"
+  ])
+  #
+  if test "$tst_links_ioctlsocket_camel" = "yes"; then
+    AC_MSG_CHECKING([if IoctlSocket is prototyped])
+    AC_EGREP_CPP([IoctlSocket],[
+      $cares_includes_stropts
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_ioctlsocket_camel="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_ioctlsocket_camel="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_ioctlsocket_camel" = "yes"; then
+    AC_MSG_CHECKING([if IoctlSocket is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_stropts
+      ]],[[
+        if(0 != IoctlSocket(0, 0, 0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_ioctlsocket_camel="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_ioctlsocket_camel="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_ioctlsocket_camel" = "yes"; then
+    AC_MSG_CHECKING([if IoctlSocket usage allowed])
+    if test "x$cares_disallow_ioctlsocket_camel" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_ioctlsocket_camel="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_ioctlsocket_camel="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if IoctlSocket might be used])
+  if test "$tst_links_ioctlsocket_camel" = "yes" &&
+     test "$tst_proto_ioctlsocket_camel" = "yes" &&
+     test "$tst_compi_ioctlsocket_camel" = "yes" &&
+     test "$tst_allow_ioctlsocket_camel" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_IOCTLSOCKET_CAMEL, 1,
+      [Define to 1 if you have the IoctlSocket camel case function.])
+    ac_cv_func_ioctlsocket_camel="yes"
+    CARES_CHECK_FUNC_IOCTLSOCKET_CAMEL_FIONBIO
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_ioctlsocket_camel="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_IOCTLSOCKET_CAMEL_FIONBIO
+dnl -------------------------------------------------
+dnl Verify if IoctlSocket with FIONBIO command is available,
+dnl can be compiled, and seems to work. If all of these are
+dnl true, then HAVE_IOCTLSOCKET_CAMEL_FIONBIO will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_IOCTLSOCKET_CAMEL_FIONBIO], [
+  #
+  tst_compi_ioctlsocket_camel_fionbio="unknown"
+  tst_allow_ioctlsocket_camel_fionbio="unknown"
+  #
+  if test "$ac_cv_func_ioctlsocket_camel" = "yes"; then
+    AC_MSG_CHECKING([if IoctlSocket FIONBIO is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_stropts
+      ]],[[
+        long flags = 0;
+        if(0 != ioctlsocket(0, FIONBIO, &flags))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_ioctlsocket_camel_fionbio="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_ioctlsocket_camel_fionbio="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_ioctlsocket_camel_fionbio" = "yes"; then
+    AC_MSG_CHECKING([if IoctlSocket FIONBIO usage allowed])
+    if test "x$cares_disallow_ioctlsocket_camel_fionbio" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_ioctlsocket_camel_fionbio="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_ioctlsocket_camel_fionbio="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if IoctlSocket FIONBIO might be used])
+  if test "$tst_compi_ioctlsocket_camel_fionbio" = "yes" &&
+     test "$tst_allow_ioctlsocket_camel_fionbio" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_IOCTLSOCKET_CAMEL_FIONBIO, 1,
+      [Define to 1 if you have a working IoctlSocket camel case FIONBIO function.])
+    ac_cv_func_ioctlsocket_camel_fionbio="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_ioctlsocket_camel_fionbio="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_SETSOCKOPT
+dnl -------------------------------------------------
+dnl Verify if setsockopt is available, prototyped, and
+dnl can be compiled. If all of these are true, and
+dnl usage has not been previously disallowed with
+dnl shell variable cares_disallow_setsockopt, then
+dnl HAVE_SETSOCKOPT will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_SETSOCKOPT], [
+  AC_REQUIRE([CARES_INCLUDES_WINSOCK2])dnl
+  AC_REQUIRE([CARES_INCLUDES_SYS_SOCKET])dnl
+  #
+  tst_links_setsockopt="unknown"
+  tst_proto_setsockopt="unknown"
+  tst_compi_setsockopt="unknown"
+  tst_allow_setsockopt="unknown"
+  #
+  AC_MSG_CHECKING([if setsockopt can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_PROGRAM([[
+      $cares_includes_winsock2
+      $cares_includes_sys_socket
+    ]],[[
+      if(0 != setsockopt(0, 0, 0, 0, 0))
+        return 1;
+    ]])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_setsockopt="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_setsockopt="no"
+  ])
+  #
+  if test "$tst_links_setsockopt" = "yes"; then
+    AC_MSG_CHECKING([if setsockopt is prototyped])
+    AC_EGREP_CPP([setsockopt],[
+      $cares_includes_winsock2
+      $cares_includes_sys_socket
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_setsockopt="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_setsockopt="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_setsockopt" = "yes"; then
+    AC_MSG_CHECKING([if setsockopt is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_winsock2
+        $cares_includes_sys_socket
+      ]],[[
+        if(0 != setsockopt(0, 0, 0, 0, 0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_setsockopt="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_setsockopt="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_setsockopt" = "yes"; then
+    AC_MSG_CHECKING([if setsockopt usage allowed])
+    if test "x$cares_disallow_setsockopt" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_setsockopt="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_setsockopt="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if setsockopt might be used])
+  if test "$tst_links_setsockopt" = "yes" &&
+     test "$tst_proto_setsockopt" = "yes" &&
+     test "$tst_compi_setsockopt" = "yes" &&
+     test "$tst_allow_setsockopt" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_SETSOCKOPT, 1,
+      [Define to 1 if you have the setsockopt function.])
+    ac_cv_func_setsockopt="yes"
+    CARES_CHECK_FUNC_SETSOCKOPT_SO_NONBLOCK
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_setsockopt="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_SETSOCKOPT_SO_NONBLOCK
+dnl -------------------------------------------------
+dnl Verify if setsockopt with the SO_NONBLOCK command is
+dnl available, can be compiled, and seems to work. If
+dnl all of these are true, then HAVE_SETSOCKOPT_SO_NONBLOCK
+dnl will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_SETSOCKOPT_SO_NONBLOCK], [
+  #
+  tst_compi_setsockopt_so_nonblock="unknown"
+  tst_allow_setsockopt_so_nonblock="unknown"
+  #
+  if test "$ac_cv_func_setsockopt" = "yes"; then
+    AC_MSG_CHECKING([if setsockopt SO_NONBLOCK is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_winsock2
+        $cares_includes_sys_socket
+      ]],[[
+        if(0 != setsockopt(0, SOL_SOCKET, SO_NONBLOCK, 0, 0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_setsockopt_so_nonblock="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_setsockopt_so_nonblock="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_setsockopt_so_nonblock" = "yes"; then
+    AC_MSG_CHECKING([if setsockopt SO_NONBLOCK usage allowed])
+    if test "x$cares_disallow_setsockopt_so_nonblock" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_setsockopt_so_nonblock="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_setsockopt_so_nonblock="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if setsockopt SO_NONBLOCK might be used])
+  if test "$tst_compi_setsockopt_so_nonblock" = "yes" &&
+     test "$tst_allow_setsockopt_so_nonblock" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_SETSOCKOPT_SO_NONBLOCK, 1,
+      [Define to 1 if you have a working setsockopt SO_NONBLOCK function.])
+    ac_cv_func_setsockopt_so_nonblock="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_setsockopt_so_nonblock="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_SOCKET
+dnl -------------------------------------------------
+dnl Verify if socket is available, prototyped, and
+dnl can be compiled. If all of these are true, and
+dnl usage has not been previously disallowed with
+dnl shell variable cares_disallow_socket, then
+dnl HAVE_SOCKET will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_SOCKET], [
+  AC_REQUIRE([CARES_INCLUDES_WINSOCK2])dnl
+  AC_REQUIRE([CARES_INCLUDES_SYS_SOCKET])dnl
+  AC_REQUIRE([CARES_INCLUDES_SOCKET])dnl
+  #
+  tst_links_socket="unknown"
+  tst_proto_socket="unknown"
+  tst_compi_socket="unknown"
+  tst_allow_socket="unknown"
+  #
+  AC_MSG_CHECKING([if socket can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_PROGRAM([[
+      $cares_includes_winsock2
+      $cares_includes_sys_socket
+      $cares_includes_socket
+    ]],[[
+      if(0 != socket(0, 0, 0))
+        return 1;
+    ]])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_socket="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_socket="no"
+  ])
+  #
+  if test "$tst_links_socket" = "yes"; then
+    AC_MSG_CHECKING([if socket is prototyped])
+    AC_EGREP_CPP([socket],[
+      $cares_includes_winsock2
+      $cares_includes_sys_socket
+      $cares_includes_socket
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_socket="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_socket="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_socket" = "yes"; then
+    AC_MSG_CHECKING([if socket is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_winsock2
+        $cares_includes_sys_socket
+        $cares_includes_socket
+      ]],[[
+        if(0 != socket(0, 0, 0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_socket="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_socket="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_socket" = "yes"; then
+    AC_MSG_CHECKING([if socket usage allowed])
+    if test "x$cares_disallow_socket" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_socket="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_socket="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if socket might be used])
+  if test "$tst_links_socket" = "yes" &&
+     test "$tst_proto_socket" = "yes" &&
+     test "$tst_compi_socket" = "yes" &&
+     test "$tst_allow_socket" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_SOCKET, 1,
+      [Define to 1 if you have the socket function.])
+    ac_cv_func_socket="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_socket="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_STRCASECMP
+dnl -------------------------------------------------
+dnl Verify if strcasecmp is available, prototyped, and
+dnl can be compiled. If all of these are true, and
+dnl usage has not been previously disallowed with
+dnl shell variable cares_disallow_strcasecmp, then
+dnl HAVE_STRCASECMP will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_STRCASECMP], [
+  AC_REQUIRE([CARES_INCLUDES_STRING])dnl
+  #
+  tst_links_strcasecmp="unknown"
+  tst_proto_strcasecmp="unknown"
+  tst_compi_strcasecmp="unknown"
+  tst_allow_strcasecmp="unknown"
+  #
+  AC_MSG_CHECKING([if strcasecmp can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([strcasecmp])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_strcasecmp="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_strcasecmp="no"
+  ])
+  #
+  if test "$tst_links_strcasecmp" = "yes"; then
+    AC_MSG_CHECKING([if strcasecmp is prototyped])
+    AC_EGREP_CPP([strcasecmp],[
+      $cares_includes_string
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_strcasecmp="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_strcasecmp="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_strcasecmp" = "yes"; then
+    AC_MSG_CHECKING([if strcasecmp is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_string
+      ]],[[
+        if(0 != strcasecmp(0, 0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_strcasecmp="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_strcasecmp="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_strcasecmp" = "yes"; then
+    AC_MSG_CHECKING([if strcasecmp usage allowed])
+    if test "x$cares_disallow_strcasecmp" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_strcasecmp="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_strcasecmp="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if strcasecmp might be used])
+  if test "$tst_links_strcasecmp" = "yes" &&
+     test "$tst_proto_strcasecmp" = "yes" &&
+     test "$tst_compi_strcasecmp" = "yes" &&
+     test "$tst_allow_strcasecmp" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_STRCASECMP, 1,
+      [Define to 1 if you have the strcasecmp function.])
+    ac_cv_func_strcasecmp="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_strcasecmp="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_STRCMPI
+dnl -------------------------------------------------
+dnl Verify if strcmpi is available, prototyped, and
+dnl can be compiled. If all of these are true, and
+dnl usage has not been previously disallowed with
+dnl shell variable cares_disallow_strcmpi, then
+dnl HAVE_STRCMPI will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_STRCMPI], [
+  AC_REQUIRE([CARES_INCLUDES_STRING])dnl
+  #
+  tst_links_strcmpi="unknown"
+  tst_proto_strcmpi="unknown"
+  tst_compi_strcmpi="unknown"
+  tst_allow_strcmpi="unknown"
+  #
+  AC_MSG_CHECKING([if strcmpi can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([strcmpi])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_strcmpi="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_strcmpi="no"
+  ])
+  #
+  if test "$tst_links_strcmpi" = "yes"; then
+    AC_MSG_CHECKING([if strcmpi is prototyped])
+    AC_EGREP_CPP([strcmpi],[
+      $cares_includes_string
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_strcmpi="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_strcmpi="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_strcmpi" = "yes"; then
+    AC_MSG_CHECKING([if strcmpi is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_string
+      ]],[[
+        if(0 != strcmpi(0, 0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_strcmpi="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_strcmpi="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_strcmpi" = "yes"; then
+    AC_MSG_CHECKING([if strcmpi usage allowed])
+    if test "x$cares_disallow_strcmpi" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_strcmpi="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_strcmpi="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if strcmpi might be used])
+  if test "$tst_links_strcmpi" = "yes" &&
+     test "$tst_proto_strcmpi" = "yes" &&
+     test "$tst_compi_strcmpi" = "yes" &&
+     test "$tst_allow_strcmpi" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_STRCMPI, 1,
+      [Define to 1 if you have the strcmpi function.])
+    ac_cv_func_strcmpi="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_strcmpi="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_STRDUP
+dnl -------------------------------------------------
+dnl Verify if strdup is available, prototyped, and
+dnl can be compiled. If all of these are true, and
+dnl usage has not been previously disallowed with
+dnl shell variable cares_disallow_strdup, then
+dnl HAVE_STRDUP will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_STRDUP], [
+  AC_REQUIRE([CARES_INCLUDES_STRING])dnl
+  #
+  tst_links_strdup="unknown"
+  tst_proto_strdup="unknown"
+  tst_compi_strdup="unknown"
+  tst_allow_strdup="unknown"
+  #
+  AC_MSG_CHECKING([if strdup can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([strdup])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_strdup="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_strdup="no"
+  ])
+  #
+  if test "$tst_links_strdup" = "yes"; then
+    AC_MSG_CHECKING([if strdup is prototyped])
+    AC_EGREP_CPP([strdup],[
+      $cares_includes_string
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_strdup="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_strdup="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_strdup" = "yes"; then
+    AC_MSG_CHECKING([if strdup is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_string
+      ]],[[
+        if(0 != strdup(0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_strdup="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_strdup="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_strdup" = "yes"; then
+    AC_MSG_CHECKING([if strdup usage allowed])
+    if test "x$cares_disallow_strdup" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_strdup="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_strdup="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if strdup might be used])
+  if test "$tst_links_strdup" = "yes" &&
+     test "$tst_proto_strdup" = "yes" &&
+     test "$tst_compi_strdup" = "yes" &&
+     test "$tst_allow_strdup" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_STRDUP, 1,
+      [Define to 1 if you have the strdup function.])
+    ac_cv_func_strdup="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_strdup="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_STRICMP
+dnl -------------------------------------------------
+dnl Verify if stricmp is available, prototyped, and
+dnl can be compiled. If all of these are true, and
+dnl usage has not been previously disallowed with
+dnl shell variable cares_disallow_stricmp, then
+dnl HAVE_STRICMP will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_STRICMP], [
+  AC_REQUIRE([CARES_INCLUDES_STRING])dnl
+  #
+  tst_links_stricmp="unknown"
+  tst_proto_stricmp="unknown"
+  tst_compi_stricmp="unknown"
+  tst_allow_stricmp="unknown"
+  #
+  AC_MSG_CHECKING([if stricmp can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([stricmp])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_stricmp="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_stricmp="no"
+  ])
+  #
+  if test "$tst_links_stricmp" = "yes"; then
+    AC_MSG_CHECKING([if stricmp is prototyped])
+    AC_EGREP_CPP([stricmp],[
+      $cares_includes_string
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_stricmp="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_stricmp="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_stricmp" = "yes"; then
+    AC_MSG_CHECKING([if stricmp is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_string
+      ]],[[
+        if(0 != stricmp(0, 0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_stricmp="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_stricmp="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_stricmp" = "yes"; then
+    AC_MSG_CHECKING([if stricmp usage allowed])
+    if test "x$cares_disallow_stricmp" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_stricmp="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_stricmp="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if stricmp might be used])
+  if test "$tst_links_stricmp" = "yes" &&
+     test "$tst_proto_stricmp" = "yes" &&
+     test "$tst_compi_stricmp" = "yes" &&
+     test "$tst_allow_stricmp" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_STRICMP, 1,
+      [Define to 1 if you have the stricmp function.])
+    ac_cv_func_stricmp="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_stricmp="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_STRNCASECMP
+dnl -------------------------------------------------
+dnl Verify if strncasecmp is available, prototyped, and
+dnl can be compiled. If all of these are true, and
+dnl usage has not been previously disallowed with
+dnl shell variable cares_disallow_strncasecmp, then
+dnl HAVE_STRNCASECMP will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_STRNCASECMP], [
+  AC_REQUIRE([CARES_INCLUDES_STRING])dnl
+  #
+  tst_links_strncasecmp="unknown"
+  tst_proto_strncasecmp="unknown"
+  tst_compi_strncasecmp="unknown"
+  tst_allow_strncasecmp="unknown"
+  #
+  AC_MSG_CHECKING([if strncasecmp can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([strncasecmp])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_strncasecmp="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_strncasecmp="no"
+  ])
+  #
+  if test "$tst_links_strncasecmp" = "yes"; then
+    AC_MSG_CHECKING([if strncasecmp is prototyped])
+    AC_EGREP_CPP([strncasecmp],[
+      $cares_includes_string
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_strncasecmp="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_strncasecmp="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_strncasecmp" = "yes"; then
+    AC_MSG_CHECKING([if strncasecmp is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_string
+      ]],[[
+        if(0 != strncasecmp(0, 0, 0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_strncasecmp="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_strncasecmp="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_strncasecmp" = "yes"; then
+    AC_MSG_CHECKING([if strncasecmp usage allowed])
+    if test "x$cares_disallow_strncasecmp" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_strncasecmp="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_strncasecmp="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if strncasecmp might be used])
+  if test "$tst_links_strncasecmp" = "yes" &&
+     test "$tst_proto_strncasecmp" = "yes" &&
+     test "$tst_compi_strncasecmp" = "yes" &&
+     test "$tst_allow_strncasecmp" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_STRNCASECMP, 1,
+      [Define to 1 if you have the strncasecmp function.])
+    ac_cv_func_strncasecmp="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_strncasecmp="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_STRNCMPI
+dnl -------------------------------------------------
+dnl Verify if strncmpi is available, prototyped, and
+dnl can be compiled. If all of these are true, and
+dnl usage has not been previously disallowed with
+dnl shell variable cares_disallow_strncmpi, then
+dnl HAVE_STRNCMPI will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_STRNCMPI], [
+  AC_REQUIRE([CARES_INCLUDES_STRING])dnl
+  #
+  tst_links_strncmpi="unknown"
+  tst_proto_strncmpi="unknown"
+  tst_compi_strncmpi="unknown"
+  tst_allow_strncmpi="unknown"
+  #
+  AC_MSG_CHECKING([if strncmpi can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([strncmpi])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_strncmpi="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_strncmpi="no"
+  ])
+  #
+  if test "$tst_links_strncmpi" = "yes"; then
+    AC_MSG_CHECKING([if strncmpi is prototyped])
+    AC_EGREP_CPP([strncmpi],[
+      $cares_includes_string
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_strncmpi="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_strncmpi="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_strncmpi" = "yes"; then
+    AC_MSG_CHECKING([if strncmpi is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_string
+      ]],[[
+        if(0 != strncmpi(0, 0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_strncmpi="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_strncmpi="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_strncmpi" = "yes"; then
+    AC_MSG_CHECKING([if strncmpi usage allowed])
+    if test "x$cares_disallow_strncmpi" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_strncmpi="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_strncmpi="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if strncmpi might be used])
+  if test "$tst_links_strncmpi" = "yes" &&
+     test "$tst_proto_strncmpi" = "yes" &&
+     test "$tst_compi_strncmpi" = "yes" &&
+     test "$tst_allow_strncmpi" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_STRNCMPI, 1,
+      [Define to 1 if you have the strncmpi function.])
+    ac_cv_func_strncmpi="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_strncmpi="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_STRNICMP
+dnl -------------------------------------------------
+dnl Verify if strnicmp is available, prototyped, and
+dnl can be compiled. If all of these are true, and
+dnl usage has not been previously disallowed with
+dnl shell variable cares_disallow_strnicmp, then
+dnl HAVE_STRNICMP will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_STRNICMP], [
+  AC_REQUIRE([CARES_INCLUDES_STRING])dnl
+  #
+  tst_links_strnicmp="unknown"
+  tst_proto_strnicmp="unknown"
+  tst_compi_strnicmp="unknown"
+  tst_allow_strnicmp="unknown"
+  #
+  AC_MSG_CHECKING([if strnicmp can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([strnicmp])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_strnicmp="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_strnicmp="no"
+  ])
+  #
+  if test "$tst_links_strnicmp" = "yes"; then
+    AC_MSG_CHECKING([if strnicmp is prototyped])
+    AC_EGREP_CPP([strnicmp],[
+      $cares_includes_string
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_strnicmp="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_strnicmp="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_strnicmp" = "yes"; then
+    AC_MSG_CHECKING([if strnicmp is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_string
+      ]],[[
+        if(0 != strnicmp(0, 0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_strnicmp="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_strnicmp="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_strnicmp" = "yes"; then
+    AC_MSG_CHECKING([if strnicmp usage allowed])
+    if test "x$cares_disallow_strnicmp" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_strnicmp="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_strnicmp="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if strnicmp might be used])
+  if test "$tst_links_strnicmp" = "yes" &&
+     test "$tst_proto_strnicmp" = "yes" &&
+     test "$tst_compi_strnicmp" = "yes" &&
+     test "$tst_allow_strnicmp" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_STRNICMP, 1,
+      [Define to 1 if you have the strnicmp function.])
+    ac_cv_func_strnicmp="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_strnicmp="no"
+  fi
+])
+
+
+dnl CARES_CHECK_FUNC_WRITEV
+dnl -------------------------------------------------
+dnl Verify if writev is available, prototyped, and
+dnl can be compiled. If all of these are true, and
+dnl usage has not been previously disallowed with
+dnl shell variable cares_disallow_writev, then
+dnl HAVE_WRITEV will be defined.
+
+AC_DEFUN([CARES_CHECK_FUNC_WRITEV], [
+  AC_REQUIRE([CARES_INCLUDES_SYS_UIO])dnl
+  #
+  tst_links_writev="unknown"
+  tst_proto_writev="unknown"
+  tst_compi_writev="unknown"
+  tst_allow_writev="unknown"
+  #
+  AC_MSG_CHECKING([if writev can be linked])
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([writev])
+  ],[
+    AC_MSG_RESULT([yes])
+    tst_links_writev="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tst_links_writev="no"
+  ])
+  #
+  if test "$tst_links_writev" = "yes"; then
+    AC_MSG_CHECKING([if writev is prototyped])
+    AC_EGREP_CPP([writev],[
+      $cares_includes_sys_uio
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_proto_writev="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_proto_writev="no"
+    ])
+  fi
+  #
+  if test "$tst_proto_writev" = "yes"; then
+    AC_MSG_CHECKING([if writev is compilable])
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+        $cares_includes_sys_uio
+      ]],[[
+        if(0 != writev(0, 0, 0))
+          return 1;
+      ]])
+    ],[
+      AC_MSG_RESULT([yes])
+      tst_compi_writev="yes"
+    ],[
+      AC_MSG_RESULT([no])
+      tst_compi_writev="no"
+    ])
+  fi
+  #
+  if test "$tst_compi_writev" = "yes"; then
+    AC_MSG_CHECKING([if writev usage allowed])
+    if test "x$cares_disallow_writev" != "xyes"; then
+      AC_MSG_RESULT([yes])
+      tst_allow_writev="yes"
+    else
+      AC_MSG_RESULT([no])
+      tst_allow_writev="no"
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if writev might be used])
+  if test "$tst_links_writev" = "yes" &&
+     test "$tst_proto_writev" = "yes" &&
+     test "$tst_compi_writev" = "yes" &&
+     test "$tst_allow_writev" = "yes"; then
+    AC_MSG_RESULT([yes])
+    AC_DEFINE_UNQUOTED(HAVE_WRITEV, 1,
+      [Define to 1 if you have the writev function.])
+    ac_cv_func_writev="yes"
+  else
+    AC_MSG_RESULT([no])
+    ac_cv_func_writev="no"
+  fi
+])
diff --git a/src/c-ares/m4/cares-override.m4 b/src/c-ares/m4/cares-override.m4
new file mode 100644
index 000000000..c7400fc9c
--- /dev/null
+++ b/src/c-ares/m4/cares-override.m4
@@ -0,0 +1,76 @@
+#***************************************************************************
+#***************************************************************************
+
+# File version for 'aclocal' use. Keep it a single number.
+# serial 8
+
+dnl CARES_OVERRIDE_AUTOCONF
+dnl -------------------------------------------------
+dnl Placing a call to this macro in configure.ac after
+dnl the one to AC_INIT will make macros in this file
+dnl visible to the rest of the compilation overriding
+dnl those from Autoconf.
+
+AC_DEFUN([CARES_OVERRIDE_AUTOCONF], [
+AC_BEFORE([$0],[AC_PROG_LIBTOOL])
+# using cares-override.m4
+])
+
+dnl Override Autoconf's AC_LANG_PROGRAM (C)
+dnl -------------------------------------------------
+dnl This is done to prevent compiler warning
+dnl 'function declaration isn't a prototype'
+dnl in function main. This requires at least
+dnl a c89 compiler and does not suport K&R.
+
+m4_define([AC_LANG_PROGRAM(C)],
+[$1
+int main (void)
+{
+$2
+ ;
+ return 0;
+}])
+
+dnl Override Autoconf's AC_LANG_CALL (C)
+dnl -------------------------------------------------
+dnl This is a backport of Autoconf's 2.60 with the
+dnl embedded comments that hit the resulting script
+dnl removed. This is done to reduce configure size
+dnl and use fixed macro across Autoconf versions.
+
+m4_define([AC_LANG_CALL(C)],
+[AC_LANG_PROGRAM([$1
+m4_if([$2], [main], ,
+[
+#ifdef __cplusplus
+extern "C"
+#endif
+char $2 ();])], [return $2 ();])])
+
+dnl Override Autoconf's AC_LANG_FUNC_LINK_TRY (C)
+dnl -------------------------------------------------
+dnl This is a backport of Autoconf's 2.60 with the
+dnl embedded comments that hit the resulting script
+dnl removed. This is done to reduce configure size
+dnl and use fixed macro across Autoconf versions.
+
+m4_define([AC_LANG_FUNC_LINK_TRY(C)],
+[AC_LANG_PROGRAM(
+[
+#define $1 innocuous_$1
+#ifdef __STDC__
+# include <limits.h>
+#else
+# include <assert.h>
+#endif
+#undef $1
+#ifdef __cplusplus
+extern "C"
+#endif
+char $1 ();
+#if defined __stub_$1 || defined __stub___$1
+choke me
+#endif
+], [return $1 ();])])
+
diff --git a/src/c-ares/m4/cares-reentrant.m4 b/src/c-ares/m4/cares-reentrant.m4
new file mode 100644
index 000000000..052326b3c
--- /dev/null
+++ b/src/c-ares/m4/cares-reentrant.m4
@@ -0,0 +1,611 @@
+#***************************************************************************
+# $Id$
+#
+# Copyright (C) 2008 - 2009 by Daniel Stenberg et al
+#
+# Permission to use, copy, modify, and distribute this software and its
+# documentation for any purpose and without fee is hereby granted, provided
+# that the above copyright notice appear in all copies and that both that
+# copyright notice and this permission notice appear in supporting
+# documentation, and that the name of M.I.T. not be used in advertising or
+# publicity pertaining to distribution of the software without specific,
+# written prior permission.  M.I.T. makes no representations about the
+# suitability of this software for any purpose.  It is provided "as is"
+# without express or implied warranty.
+#
+#***************************************************************************
+
+# File version for 'aclocal' use. Keep it a single number.
+# serial 6
+
+dnl Note 1
+dnl ------
+dnl None of the CARES_CHECK_NEED_REENTRANT_* macros shall use HAVE_FOO_H to
+dnl conditionally include header files. These macros are used early in the
+dnl configure process much before header file availability is known.
+
+
+dnl CARES_CHECK_NEED_REENTRANT_ERRNO
+dnl -------------------------------------------------
+dnl Checks if the preprocessor _REENTRANT definition
+dnl makes errno available as a preprocessor macro.
+
+AC_DEFUN([CARES_CHECK_NEED_REENTRANT_ERRNO], [
+  AC_COMPILE_IFELSE([
+    AC_LANG_PROGRAM([[
+#include <errno.h>
+    ]],[[
+      if(0 != errno)
+        return 1;
+    ]])
+  ],[
+    tmp_errno="yes"
+  ],[
+    tmp_errno="no"
+  ])
+  if test "$tmp_errno" = "yes"; then
+    AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM([[
+#include <errno.h>
+      ]],[[
+#ifdef errno
+        int dummy=1;
+#else
+        force compilation error
+#endif
+      ]])
+    ],[
+      tmp_errno="errno_macro_defined"
+    ],[
+      AC_COMPILE_IFELSE([
+        AC_LANG_PROGRAM([[
+#define _REENTRANT
+#include <errno.h>
+        ]],[[
+#ifdef errno
+          int dummy=1;
+#else
+          force compilation error
+#endif
+        ]])
+      ],[
+        tmp_errno="errno_macro_needs_reentrant"
+        tmp_need_reentrant="yes"
+      ])
+    ])
+  fi
+])
+
+
+dnl CARES_CHECK_NEED_REENTRANT_GMTIME_R
+dnl -------------------------------------------------
+dnl Checks if the preprocessor _REENTRANT definition
+dnl makes function gmtime_r compiler visible.
+
+AC_DEFUN([CARES_CHECK_NEED_REENTRANT_GMTIME_R], [
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([gmtime_r])
+  ],[
+    tmp_gmtime_r="yes"
+  ],[
+    tmp_gmtime_r="no"
+  ])
+  if test "$tmp_gmtime_r" = "yes"; then
+    AC_EGREP_CPP([gmtime_r],[
+#include <sys/types.h>
+#include <time.h>
+    ],[
+      tmp_gmtime_r="proto_declared"
+    ],[
+      AC_EGREP_CPP([gmtime_r],[
+#define _REENTRANT
+#include <sys/types.h>
+#include <time.h>
+      ],[
+        tmp_gmtime_r="proto_needs_reentrant"
+        tmp_need_reentrant="yes"
+      ])
+    ])
+  fi
+])
+
+
+dnl CARES_CHECK_NEED_REENTRANT_LOCALTIME_R
+dnl -------------------------------------------------
+dnl Checks if the preprocessor _REENTRANT definition
+dnl makes function localtime_r compiler visible.
+
+AC_DEFUN([CARES_CHECK_NEED_REENTRANT_LOCALTIME_R], [
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([localtime_r])
+  ],[
+    tmp_localtime_r="yes"
+  ],[
+    tmp_localtime_r="no"
+  ])
+  if test "$tmp_localtime_r" = "yes"; then
+    AC_EGREP_CPP([localtime_r],[
+#include <sys/types.h>
+#include <time.h>
+    ],[
+      tmp_localtime_r="proto_declared"
+    ],[
+      AC_EGREP_CPP([localtime_r],[
+#define _REENTRANT
+#include <sys/types.h>
+#include <time.h>
+      ],[
+        tmp_localtime_r="proto_needs_reentrant"
+        tmp_need_reentrant="yes"
+      ])
+    ])
+  fi
+])
+
+
+dnl CARES_CHECK_NEED_REENTRANT_STRERROR_R
+dnl -------------------------------------------------
+dnl Checks if the preprocessor _REENTRANT definition
+dnl makes function strerror_r compiler visible.
+
+AC_DEFUN([CARES_CHECK_NEED_REENTRANT_STRERROR_R], [
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([strerror_r])
+  ],[
+    tmp_strerror_r="yes"
+  ],[
+    tmp_strerror_r="no"
+  ])
+  if test "$tmp_strerror_r" = "yes"; then
+    AC_EGREP_CPP([strerror_r],[
+#include <sys/types.h>
+#include <string.h>
+    ],[
+      tmp_strerror_r="proto_declared"
+    ],[
+      AC_EGREP_CPP([strerror_r],[
+#define _REENTRANT
+#include <sys/types.h>
+#include <string.h>
+      ],[
+        tmp_strerror_r="proto_needs_reentrant"
+        tmp_need_reentrant="yes"
+      ])
+    ])
+  fi
+])
+
+
+dnl CARES_CHECK_NEED_REENTRANT_STRTOK_R
+dnl -------------------------------------------------
+dnl Checks if the preprocessor _REENTRANT definition
+dnl makes function strtok_r compiler visible.
+
+AC_DEFUN([CARES_CHECK_NEED_REENTRANT_STRTOK_R], [
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([strtok_r])
+  ],[
+    tmp_strtok_r="yes"
+  ],[
+    tmp_strtok_r="no"
+  ])
+  if test "$tmp_strtok_r" = "yes"; then
+    AC_EGREP_CPP([strtok_r],[
+#include <sys/types.h>
+#include <string.h>
+    ],[
+      tmp_strtok_r="proto_declared"
+    ],[
+      AC_EGREP_CPP([strtok_r],[
+#define _REENTRANT
+#include <sys/types.h>
+#include <string.h>
+      ],[
+        tmp_strtok_r="proto_needs_reentrant"
+        tmp_need_reentrant="yes"
+      ])
+    ])
+  fi
+])
+
+
+dnl CARES_CHECK_NEED_REENTRANT_INET_NTOA_R
+dnl -------------------------------------------------
+dnl Checks if the preprocessor _REENTRANT definition
+dnl makes function inet_ntoa_r compiler visible.
+
+AC_DEFUN([CARES_CHECK_NEED_REENTRANT_INET_NTOA_R], [
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([inet_ntoa_r])
+  ],[
+    tmp_inet_ntoa_r="yes"
+  ],[
+    tmp_inet_ntoa_r="no"
+  ])
+  if test "$tmp_inet_ntoa_r" = "yes"; then
+    AC_EGREP_CPP([inet_ntoa_r],[
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+    ],[
+      tmp_inet_ntoa_r="proto_declared"
+    ],[
+      AC_EGREP_CPP([inet_ntoa_r],[
+#define _REENTRANT
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+      ],[
+        tmp_inet_ntoa_r="proto_needs_reentrant"
+        tmp_need_reentrant="yes"
+      ])
+    ])
+  fi
+])
+
+
+dnl CARES_CHECK_NEED_REENTRANT_GETHOSTBYADDR_R
+dnl -------------------------------------------------
+dnl Checks if the preprocessor _REENTRANT definition
+dnl makes function gethostbyaddr_r compiler visible.
+
+AC_DEFUN([CARES_CHECK_NEED_REENTRANT_GETHOSTBYADDR_R], [
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([gethostbyaddr_r])
+  ],[
+    tmp_gethostbyaddr_r="yes"
+  ],[
+    tmp_gethostbyaddr_r="no"
+  ])
+  if test "$tmp_gethostbyaddr_r" = "yes"; then
+    AC_EGREP_CPP([gethostbyaddr_r],[
+#include <sys/types.h>
+#include <netdb.h>
+    ],[
+      tmp_gethostbyaddr_r="proto_declared"
+    ],[
+      AC_EGREP_CPP([gethostbyaddr_r],[
+#define _REENTRANT
+#include <sys/types.h>
+#include <netdb.h>
+      ],[
+        tmp_gethostbyaddr_r="proto_needs_reentrant"
+        tmp_need_reentrant="yes"
+      ])
+    ])
+  fi
+])
+
+
+dnl CARES_CHECK_NEED_REENTRANT_GETHOSTBYNAME_R
+dnl -------------------------------------------------
+dnl Checks if the preprocessor _REENTRANT definition
+dnl makes function gethostbyname_r compiler visible.
+
+AC_DEFUN([CARES_CHECK_NEED_REENTRANT_GETHOSTBYNAME_R], [
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([gethostbyname_r])
+  ],[
+    tmp_gethostbyname_r="yes"
+  ],[
+    tmp_gethostbyname_r="no"
+  ])
+  if test "$tmp_gethostbyname_r" = "yes"; then
+    AC_EGREP_CPP([gethostbyname_r],[
+#include <sys/types.h>
+#include <netdb.h>
+    ],[
+      tmp_gethostbyname_r="proto_declared"
+    ],[
+      AC_EGREP_CPP([gethostbyname_r],[
+#define _REENTRANT
+#include <sys/types.h>
+#include <netdb.h>
+      ],[
+        tmp_gethostbyname_r="proto_needs_reentrant"
+        tmp_need_reentrant="yes"
+      ])
+    ])
+  fi
+])
+
+
+dnl CARES_CHECK_NEED_REENTRANT_GETPROTOBYNAME_R
+dnl -------------------------------------------------
+dnl Checks if the preprocessor _REENTRANT definition
+dnl makes function getprotobyname_r compiler visible.
+
+AC_DEFUN([CARES_CHECK_NEED_REENTRANT_GETPROTOBYNAME_R], [
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([getprotobyname_r])
+  ],[
+    tmp_getprotobyname_r="yes"
+  ],[
+    tmp_getprotobyname_r="no"
+  ])
+  if test "$tmp_getprotobyname_r" = "yes"; then
+    AC_EGREP_CPP([getprotobyname_r],[
+#include <sys/types.h>
+#include <netdb.h>
+    ],[
+      tmp_getprotobyname_r="proto_declared"
+    ],[
+      AC_EGREP_CPP([getprotobyname_r],[
+#define _REENTRANT
+#include <sys/types.h>
+#include <netdb.h>
+      ],[
+        tmp_getprotobyname_r="proto_needs_reentrant"
+        tmp_need_reentrant="yes"
+      ])
+    ])
+  fi
+])
+
+
+dnl CARES_CHECK_NEED_REENTRANT_GETSERVBYPORT_R
+dnl -------------------------------------------------
+dnl Checks if the preprocessor _REENTRANT definition
+dnl makes function getservbyport_r compiler visible.
+
+AC_DEFUN([CARES_CHECK_NEED_REENTRANT_GETSERVBYPORT_R], [
+  AC_LINK_IFELSE([
+    AC_LANG_FUNC_LINK_TRY([getservbyport_r])
+  ],[
+    tmp_getservbyport_r="yes"
+  ],[
+    tmp_getservbyport_r="no"
+  ])
+  if test "$tmp_getservbyport_r" = "yes"; then
+    AC_EGREP_CPP([getservbyport_r],[
+#include <sys/types.h>
+#include <netdb.h>
+    ],[
+      tmp_getservbyport_r="proto_declared"
+    ],[
+      AC_EGREP_CPP([getservbyport_r],[
+#define _REENTRANT
+#include <sys/types.h>
+#include <netdb.h>
+      ],[
+        tmp_getservbyport_r="proto_needs_reentrant"
+        tmp_need_reentrant="yes"
+      ])
+    ])
+  fi
+])
+
+
+dnl CARES_CHECK_NEED_REENTRANT_FUNCTIONS_R
+dnl -------------------------------------------------
+dnl Checks if the preprocessor _REENTRANT definition
+dnl makes several _r functions compiler visible.
+dnl Internal macro for CARES_CONFIGURE_REENTRANT.
+
+AC_DEFUN([CARES_CHECK_NEED_REENTRANT_FUNCTIONS_R], [
+  if test "$tmp_need_reentrant" = "no"; then
+    CARES_CHECK_NEED_REENTRANT_GMTIME_R
+  fi
+  if test "$tmp_need_reentrant" = "no"; then
+    CARES_CHECK_NEED_REENTRANT_LOCALTIME_R
+  fi
+  if test "$tmp_need_reentrant" = "no"; then
+    CARES_CHECK_NEED_REENTRANT_STRERROR_R
+  fi
+  if test "$tmp_need_reentrant" = "no"; then
+    CARES_CHECK_NEED_REENTRANT_STRTOK_R
+  fi
+  if test "$tmp_need_reentrant" = "no"; then
+    CARES_CHECK_NEED_REENTRANT_INET_NTOA_R
+  fi
+  if test "$tmp_need_reentrant" = "no"; then
+    CARES_CHECK_NEED_REENTRANT_GETHOSTBYADDR_R
+  fi
+  if test "$tmp_need_reentrant" = "no"; then
+    CARES_CHECK_NEED_REENTRANT_GETHOSTBYNAME_R
+  fi
+  if test "$tmp_need_reentrant" = "no"; then
+    CARES_CHECK_NEED_REENTRANT_GETPROTOBYNAME_R
+  fi
+  if test "$tmp_need_reentrant" = "no"; then
+    CARES_CHECK_NEED_REENTRANT_GETSERVBYPORT_R
+  fi
+])
+
+
+dnl CARES_CHECK_NEED_REENTRANT_SYSTEM
+dnl -------------------------------------------------
+dnl Checks if the preprocessor _REENTRANT definition
+dnl must be unconditionally done for this platform.
+dnl Internal macro for CARES_CONFIGURE_REENTRANT.
+
+AC_DEFUN([CARES_CHECK_NEED_REENTRANT_SYSTEM], [
+  case $host_os in
+    solaris*)
+      tmp_need_reentrant="yes"
+      ;;
+    *)
+      tmp_need_reentrant="no"
+      ;;
+  esac
+])
+
+
+dnl CARES_CHECK_NEED_THREAD_SAFE_SYSTEM
+dnl -------------------------------------------------
+dnl Checks if the preprocessor _THREAD_SAFE definition
+dnl must be unconditionally done for this platform.
+dnl Internal macro for CARES_CONFIGURE_THREAD_SAFE.
+
+AC_DEFUN([CARES_CHECK_NEED_THREAD_SAFE_SYSTEM], [
+  case $host_os in
+    aix[[123]].* | aix4.[[012]].*)
+      dnl aix 4.2 and older
+      tmp_need_thread_safe="no"
+      ;;
+    aix*)
+      dnl AIX 4.3 and newer
+      tmp_need_thread_safe="yes"
+      ;;
+    *)
+      tmp_need_thread_safe="no"
+      ;;
+  esac
+])
+
+
+dnl CARES_CONFIGURE_FROM_NOW_ON_WITH_REENTRANT
+dnl -------------------------------------------------
+dnl This macro ensures that configuration tests done
+dnl after this will execute with preprocessor symbol
+dnl _REENTRANT defined. This macro also ensures that
+dnl the generated config file defines NEED_REENTRANT
+dnl and that in turn setup.h will define _REENTRANT.
+dnl Internal macro for CARES_CONFIGURE_REENTRANT.
+
+AC_DEFUN([CARES_CONFIGURE_FROM_NOW_ON_WITH_REENTRANT], [
+AC_DEFINE(NEED_REENTRANT, 1,
+  [Define to 1 if _REENTRANT preprocessor symbol must be defined.])
+cat >>confdefs.h <<_EOF
+#ifndef _REENTRANT
+#  define _REENTRANT
+#endif
+_EOF
+])
+
+
+dnl CARES_CONFIGURE_FROM_NOW_ON_WITH_THREAD_SAFE
+dnl -------------------------------------------------
+dnl This macro ensures that configuration tests done
+dnl after this will execute with preprocessor symbol
+dnl _THREAD_SAFE defined. This macro also ensures that
+dnl the generated config file defines NEED_THREAD_SAFE
+dnl and that in turn setup.h will define _THREAD_SAFE.
+dnl Internal macro for CARES_CONFIGURE_THREAD_SAFE.
+
+AC_DEFUN([CARES_CONFIGURE_FROM_NOW_ON_WITH_THREAD_SAFE], [
+AC_DEFINE(NEED_THREAD_SAFE, 1,
+  [Define to 1 if _THREAD_SAFE preprocessor symbol must be defined.])
+cat >>confdefs.h <<_EOF
+#ifndef _THREAD_SAFE
+#  define _THREAD_SAFE
+#endif
+_EOF
+])
+
+
+dnl CARES_CONFIGURE_REENTRANT
+dnl -------------------------------------------------
+dnl This first checks if the preprocessor _REENTRANT
+dnl symbol is already defined. If it isn't currently
+dnl defined a set of checks are performed to verify
+dnl if its definition is required to make visible to
+dnl the compiler a set of *_r functions. Finally, if
+dnl _REENTRANT is already defined or needed it takes
+dnl care of making adjustments necessary to ensure
+dnl that it is defined equally for further configure
+dnl tests and generated config file.
+
+AC_DEFUN([CARES_CONFIGURE_REENTRANT], [
+  AC_PREREQ([2.50])dnl
+  #
+  AC_MSG_CHECKING([if _REENTRANT is already defined])
+  AC_COMPILE_IFELSE([
+    AC_LANG_PROGRAM([[
+    ]],[[
+#ifdef _REENTRANT
+      int dummy=1;
+#else
+      force compilation error
+#endif
+    ]])
+  ],[
+    AC_MSG_RESULT([yes])
+    tmp_reentrant_initially_defined="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tmp_reentrant_initially_defined="no"
+  ])
+  #
+  if test "$tmp_reentrant_initially_defined" = "no"; then
+    AC_MSG_CHECKING([if _REENTRANT is actually needed])
+    CARES_CHECK_NEED_REENTRANT_SYSTEM
+    if test "$tmp_need_reentrant" = "no"; then
+      CARES_CHECK_NEED_REENTRANT_ERRNO
+    fi
+    if test "$tmp_need_reentrant" = "no"; then
+      CARES_CHECK_NEED_REENTRANT_FUNCTIONS_R
+    fi
+    if test "$tmp_need_reentrant" = "yes"; then
+      AC_MSG_RESULT([yes])
+    else
+      AC_MSG_RESULT([no])
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if _REENTRANT is onwards defined])
+  if test "$tmp_reentrant_initially_defined" = "yes" ||
+    test "$tmp_need_reentrant" = "yes"; then
+    CARES_CONFIGURE_FROM_NOW_ON_WITH_REENTRANT
+    AC_MSG_RESULT([yes])
+  else
+    AC_MSG_RESULT([no])
+  fi
+  #
+])
+
+
+dnl CARES_CONFIGURE_THREAD_SAFE
+dnl -------------------------------------------------
+dnl This first checks if the preprocessor _THREAD_SAFE
+dnl symbol is already defined. If it isn't currently
+dnl defined a set of checks are performed to verify
+dnl if its definition is required. Finally, if
+dnl _THREAD_SAFE is already defined or needed it takes
+dnl care of making adjustments necessary to ensure
+dnl that it is defined equally for further configure
+dnl tests and generated config file.
+
+AC_DEFUN([CARES_CONFIGURE_THREAD_SAFE], [
+  AC_PREREQ([2.50])dnl
+  #
+  AC_MSG_CHECKING([if _THREAD_SAFE is already defined])
+  AC_COMPILE_IFELSE([
+    AC_LANG_PROGRAM([[
+    ]],[[
+#ifdef _THREAD_SAFE
+      int dummy=1;
+#else
+      force compilation error
+#endif
+    ]])
+  ],[
+    AC_MSG_RESULT([yes])
+    tmp_thread_safe_initially_defined="yes"
+  ],[
+    AC_MSG_RESULT([no])
+    tmp_thread_safe_initially_defined="no"
+  ])
+  #
+  if test "$tmp_thread_safe_initially_defined" = "no"; then
+    AC_MSG_CHECKING([if _THREAD_SAFE is actually needed])
+    CARES_CHECK_NEED_THREAD_SAFE_SYSTEM
+    if test "$tmp_need_thread_safe" = "yes"; then
+      AC_MSG_RESULT([yes])
+    else
+      AC_MSG_RESULT([no])
+    fi
+  fi
+  #
+  AC_MSG_CHECKING([if _THREAD_SAFE is onwards defined])
+  if test "$tmp_thread_safe_initially_defined" = "yes" ||
+    test "$tmp_need_thread_safe" = "yes"; then
+    CARES_CONFIGURE_FROM_NOW_ON_WITH_THREAD_SAFE
+    AC_MSG_RESULT([yes])
+  else
+    AC_MSG_RESULT([no])
+  fi
+  #
+])
diff --git a/src/c-ares/m4/xc-am-iface.m4 b/src/c-ares/m4/xc-am-iface.m4
new file mode 100644
index 000000000..1571c211f
--- /dev/null
+++ b/src/c-ares/m4/xc-am-iface.m4
@@ -0,0 +1,253 @@
+#---------------------------------------------------------------------------
+#
+# xc-am-iface.m4
+#
+# Copyright (c) 2013 Daniel Stenberg <daniel@haxx.se>
+#
+# Permission to use, copy, modify, and distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+#
+#---------------------------------------------------------------------------
+
+# serial 1
+
+
+dnl _XC_AUTOMAKE_BODY
+dnl -------------------------------------------------
+dnl Private macro.
+dnl
+dnl This macro performs embedding of automake initialization
+dnl code into configure script. When automake version 1.14 or
+dnl newer is used at configure script generation time, this
+dnl results in 'subdir-objects' automake option being used.
+dnl When using automake versions older than 1.14 this option
+dnl is not used when generating configure script.
+dnl
+dnl Existence of automake _AM_PROG_CC_C_O m4 private macro
+dnl is used to differentiate automake version 1.14 from older
+dnl ones which lack this macro.
+
+m4_define([_XC_AUTOMAKE_BODY],
+[dnl
+## --------------------------------------- ##
+##  Start of automake initialization code  ##
+## --------------------------------------- ##
+m4_ifdef([_AM_PROG_CC_C_O],
+[
+AM_INIT_AUTOMAKE([subdir-objects])
+],[
+AM_INIT_AUTOMAKE
+])dnl
+## ------------------------------------- ##
+##  End of automake initialization code  ##
+## ------------------------------------- ##
+dnl
+m4_define([$0], [])[]dnl
+])
+
+
+dnl XC_AUTOMAKE
+dnl -------------------------------------------------
+dnl Public macro.
+dnl
+dnl This macro embeds automake machinery into configure
+dnl script regardless of automake version used in order
+dnl to generate configure script.
+dnl
+dnl When using automake version 1.14 or newer, automake
+dnl initialization option 'subdir-objects' is used to
+dnl generate the configure script, otherwise this option
+dnl is not used.
+
+AC_DEFUN([XC_AUTOMAKE],
+[dnl
+AC_PREREQ([2.50])dnl
+dnl
+AC_BEFORE([$0],[AM_INIT_AUTOMAKE])dnl
+dnl
+_XC_AUTOMAKE_BODY
+dnl
+m4_ifdef([AM_INIT_AUTOMAKE],
+  [m4_undefine([AM_INIT_AUTOMAKE])])dnl
+dnl
+m4_define([$0], [])[]dnl
+])
+
+
+dnl _XC_AMEND_DISTCLEAN_BODY ([LIST-OF-SUBDIRS])
+dnl -------------------------------------------------
+dnl Private macro.
+dnl
+dnl This macro performs shell code embedding into
+dnl configure script in order to modify distclean
+dnl and maintainer-clean targets of makefiles which
+dnl are located in given list of subdirs.
+dnl
+dnl See XC_AMEND_DISTCLEAN comments for details.
+
+m4_define([_XC_AMEND_DISTCLEAN_BODY],
+[dnl
+## ---------------------------------- ##
+##  Start of distclean amending code  ##
+## ---------------------------------- ##
+
+for xc_subdir in [$1]
+do
+
+if test ! -f "$xc_subdir/Makefile"; then
+  echo "$xc_msg_err $xc_subdir/Makefile file not found. $xc_msg_abrt" >&2
+  exit 1
+fi
+
+# Fetch dependency tracking file list from Makefile include lines.
+
+xc_inc_lines=`grep '^include .*(DEPDIR)' "$xc_subdir/Makefile" 2>/dev/null`
+xc_cnt_words=`echo "$xc_inc_lines" | wc -w | tr -d "$xc_space$xc_tab"`
+
+# --disable-dependency-tracking might have been used, consequently
+# there is nothing to amend without a dependency tracking file list.
+
+if test $xc_cnt_words -gt 0; then
+
+AC_MSG_NOTICE([amending $xc_subdir/Makefile])
+
+# Build Makefile specific patch hunk.
+
+xc_p="$xc_subdir/xc_patch.tmp"
+
+xc_rm_depfiles=`echo "$xc_inc_lines" \
+  | $SED 's%include%	-rm -f%' 2>/dev/null`
+
+xc_dep_subdirs=`echo "$xc_inc_lines" \
+  | $SED 's%include[[ ]][[ ]]*%%' 2>/dev/null \
+  | $SED 's%(DEPDIR)/.*%(DEPDIR)%' 2>/dev/null \
+  | sort | uniq`
+
+echo "$xc_rm_depfiles" >$xc_p
+
+for xc_dep_dir in $xc_dep_subdirs; do
+  echo "${xc_tab}@xm_dep_cnt=\`ls $xc_dep_dir | wc -l 2>/dev/null\`; \\"            >>$xc_p
+  echo "${xc_tab}if test \$\$xm_dep_cnt -eq 0 && test -d $xc_dep_dir; then \\"      >>$xc_p
+  echo "${xc_tab}  rm -rf $xc_dep_dir; \\"                                          >>$xc_p
+  echo "${xc_tab}fi"                                                                >>$xc_p
+done
+
+# Build Makefile patching sed scripts.
+
+xc_s1="$xc_subdir/xc_script_1.tmp"
+xc_s2="$xc_subdir/xc_script_2.tmp"
+xc_s3="$xc_subdir/xc_script_3.tmp"
+
+cat >$xc_s1 <<\_EOT
+/^distclean[[ ]]*:/,/^[[^	]][[^	]]*:/{
+  s/^.*(DEPDIR)/___xc_depdir_line___/
+}
+/^maintainer-clean[[ ]]*:/,/^[[^	]][[^	]]*:/{
+  s/^.*(DEPDIR)/___xc_depdir_line___/
+}
+_EOT
+
+cat >$xc_s2 <<\_EOT
+/___xc_depdir_line___$/{
+  N
+  /___xc_depdir_line___$/D
+}
+_EOT
+
+cat >$xc_s3 <<_EOT
+/^___xc_depdir_line___/{
+  r $xc_p
+  d
+}
+_EOT
+
+# Apply patch to Makefile and cleanup.
+
+$SED -f "$xc_s1" "$xc_subdir/Makefile"      >"$xc_subdir/Makefile.tmp1"
+$SED -f "$xc_s2" "$xc_subdir/Makefile.tmp1" >"$xc_subdir/Makefile.tmp2"
+$SED -f "$xc_s3" "$xc_subdir/Makefile.tmp2" >"$xc_subdir/Makefile.tmp3"
+
+if test -f "$xc_subdir/Makefile.tmp3"; then
+  mv -f "$xc_subdir/Makefile.tmp3" "$xc_subdir/Makefile"
+fi
+
+test -f "$xc_subdir/Makefile.tmp1" && rm -f "$xc_subdir/Makefile.tmp1"
+test -f "$xc_subdir/Makefile.tmp2" && rm -f "$xc_subdir/Makefile.tmp2"
+test -f "$xc_subdir/Makefile.tmp3" && rm -f "$xc_subdir/Makefile.tmp3"
+
+test -f "$xc_p"  && rm -f "$xc_p"
+test -f "$xc_s1" && rm -f "$xc_s1"
+test -f "$xc_s2" && rm -f "$xc_s2"
+test -f "$xc_s3" && rm -f "$xc_s3"
+
+fi
+
+done
+
+## -------------------------------- ##
+##  End of distclean amending code  ##
+## -------------------------------- ##
+dnl
+m4_define([$0], [])[]dnl
+])
+
+
+dnl XC_AMEND_DISTCLEAN ([LIST-OF-SUBDIRS])
+dnl -------------------------------------------------
+dnl Public macro.
+dnl
+dnl This macro embeds shell code into configure script
+dnl that amends, at configure runtime, the distclean
+dnl and maintainer-clean targets of Makefiles located
+dnl in all subdirs given in the mandatory white-space
+dnl separated list argument.
+dnl
+dnl Embedding only takes place when using automake 1.14
+dnl or newer, otherwise amending code is not included
+dnl in generated configure script.
+dnl
+dnl distclean and maintainer-clean targets are modified
+dnl to avoid unconditional removal of dependency subdirs
+dnl which triggers distclean and maintainer-clean errors
+dnl when using automake 'subdir-objects' option along
+dnl with per-target objects and source files existing in
+dnl multiple subdirs used for different build targets.
+dnl
+dnl New behavior first removes each dependency tracking
+dnl file independently, and only removes each dependency
+dnl subdir when it finds out that it no longer holds any
+dnl dependency tracking file.
+dnl
+dnl When configure option --disable-dependency-tracking
+dnl is used no amending takes place given that there are
+dnl no dependency tracking files.
+
+AC_DEFUN([XC_AMEND_DISTCLEAN],
+[dnl
+AC_PREREQ([2.50])dnl
+dnl
+m4_ifdef([_AC_OUTPUT_MAIN_LOOP],
+  [m4_provide_if([_AC_OUTPUT_MAIN_LOOP], [],
+    [m4_fatal([call to AC_OUTPUT needed before $0])])])dnl
+dnl
+m4_if([$#], [1], [], [m4_fatal([$0: wrong number of arguments])])dnl
+m4_if([$1], [], [m4_fatal([$0: missing argument])])dnl
+dnl
+AC_REQUIRE([XC_CONFIGURE_PREAMBLE])dnl
+dnl
+m4_ifdef([_AM_PROG_CC_C_O],
+[
+_XC_AMEND_DISTCLEAN_BODY([$1])
+])dnl
+m4_define([$0], [])[]dnl
+])
+
diff --git a/src/c-ares/m4/xc-cc-check.m4 b/src/c-ares/m4/xc-cc-check.m4
new file mode 100644
index 000000000..cd5540531
--- /dev/null
+++ b/src/c-ares/m4/xc-cc-check.m4
@@ -0,0 +1,96 @@
+#---------------------------------------------------------------------------
+#
+# xc-cc-check.m4
+#
+# Copyright (c) 2013 Daniel Stenberg <daniel@haxx.se>
+#
+# Permission to use, copy, modify, and distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+#
+#---------------------------------------------------------------------------
+
+# serial 1
+
+
+dnl _XC_PROG_CC_PREAMBLE
+dnl -------------------------------------------------
+dnl Private macro.
+
+AC_DEFUN([_XC_PROG_CC_PREAMBLE], [
+  xc_prog_cc_prev_IFS=$IFS
+  xc_prog_cc_prev_LIBS=$LIBS
+  xc_prog_cc_prev_CFLAGS=$CFLAGS
+  xc_prog_cc_prev_LDFLAGS=$LDFLAGS
+  xc_prog_cc_prev_CPPFLAGS=$CPPFLAGS
+])
+
+
+dnl _XC_PROG_CC_POSTLUDE
+dnl -------------------------------------------------
+dnl Private macro.
+
+AC_DEFUN([_XC_PROG_CC_POSTLUDE], [
+  IFS=$xc_prog_cc_prev_IFS
+  LIBS=$xc_prog_cc_prev_LIBS
+  CFLAGS=$xc_prog_cc_prev_CFLAGS
+  LDFLAGS=$xc_prog_cc_prev_LDFLAGS
+  CPPFLAGS=$xc_prog_cc_prev_CPPFLAGS
+  AC_SUBST([CC])dnl
+  AC_SUBST([CPP])dnl
+  AC_SUBST([LIBS])dnl
+  AC_SUBST([CFLAGS])dnl
+  AC_SUBST([LDFLAGS])dnl
+  AC_SUBST([CPPFLAGS])dnl
+])
+
+
+dnl _XC_PROG_CC
+dnl -------------------------------------------------
+dnl Private macro.
+
+AC_DEFUN([_XC_PROG_CC], [
+  AC_REQUIRE([_XC_PROG_CC_PREAMBLE])dnl
+  AC_REQUIRE([XC_CHECK_USER_FLAGS])dnl
+  AC_REQUIRE([AC_PROG_INSTALL])dnl
+  AC_REQUIRE([AC_PROG_CC])dnl
+  AC_REQUIRE([AM_PROG_CC_C_O])dnl
+  AC_REQUIRE([AC_PROG_CPP])dnl
+  AC_REQUIRE([_XC_PROG_CC_POSTLUDE])dnl
+])
+
+
+dnl XC_CHECK_PROG_CC
+dnl -------------------------------------------------
+dnl Public macro.
+dnl
+dnl Checks for C compiler and C preprocessor programs,
+dnl while doing some previous sanity validation on user
+dnl provided LIBS, LDFLAGS, CPPFLAGS and CFLAGS values
+dnl that must succeed in order to continue execution.
+dnl
+dnl This sets variables CC and CPP, while preventing
+dnl LIBS, LDFLAGS, CFLAGS, CPPFLAGS and IFS from being
+dnl unexpectedly changed by underlying macros.
+
+AC_DEFUN([XC_CHECK_PROG_CC], [
+  AC_PREREQ([2.50])dnl
+  AC_BEFORE([$0],[_XC_PROG_CC_PREAMBLE])dnl
+  AC_BEFORE([$0],[AC_PROG_INSTALL])dnl
+  AC_BEFORE([$0],[AC_PROG_CC])dnl
+  AC_BEFORE([$0],[AM_PROG_CC_C_O])dnl
+  AC_BEFORE([$0],[AC_PROG_CPP])dnl
+  AC_BEFORE([$0],[AC_PROG_LIBTOOL])dnl
+  AC_BEFORE([$0],[AM_INIT_AUTOMAKE])dnl
+  AC_BEFORE([$0],[_XC_PROG_CC_POSTLUDE])dnl
+  AC_REQUIRE([_XC_PROG_CC])dnl
+])
+
diff --git a/src/c-ares/m4/xc-lt-iface.m4 b/src/c-ares/m4/xc-lt-iface.m4
new file mode 100644
index 000000000..0b90d5f25
--- /dev/null
+++ b/src/c-ares/m4/xc-lt-iface.m4
@@ -0,0 +1,465 @@
+#---------------------------------------------------------------------------
+#
+# xc-lt-iface.m4
+#
+# Copyright (c) 2013 Daniel Stenberg <daniel@haxx.se>
+#
+# Permission to use, copy, modify, and distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+#
+#---------------------------------------------------------------------------
+
+# serial 1
+
+
+dnl _XC_LIBTOOL_PREAMBLE
+dnl -------------------------------------------------
+dnl Private macro.
+dnl
+dnl Checks some configure script options related with
+dnl libtool and customizes its default behavior before
+dnl libtool code is actually used in script.
+
+m4_define([_XC_LIBTOOL_PREAMBLE],
+[dnl
+# ------------------------------------ #
+#  Determine libtool default behavior  #
+# ------------------------------------ #
+
+#
+# Default behavior is to enable shared and static libraries on systems
+# where libtool knows how to build both library versions, and does not
+# require separate configuration and build runs for each flavor.
+#
+
+xc_lt_want_enable_shared='yes'
+xc_lt_want_enable_static='yes'
+
+#
+# User may have disabled shared or static libraries.
+#
+case "x$enable_shared" in @%:@ (
+  xno)
+    xc_lt_want_enable_shared='no'
+    ;;
+esac
+case "x$enable_static" in @%:@ (
+  xno)
+    xc_lt_want_enable_static='no'
+    ;;
+esac
+if test "x$xc_lt_want_enable_shared" = 'xno' &&
+  test "x$xc_lt_want_enable_static" = 'xno'; then
+  AC_MSG_ERROR([can not disable shared and static libraries simultaneously])
+fi
+
+#
+# Default behavior on systems that require independent configuration
+# and build runs for shared and static is to enable shared libraries
+# and disable static ones. On these systems option '--disable-shared'
+# must be used in order to build a proper static library.
+#
+
+if test "x$xc_lt_want_enable_shared" = 'xyes' &&
+  test "x$xc_lt_want_enable_static" = 'xyes'; then
+  case $host_os in @%:@ (
+    mingw* | pw32* | cegcc* | os2* | aix*)
+      xc_lt_want_enable_static='no'
+      ;;
+  esac
+fi
+
+#
+# Make libtool aware of current shared and static library preferences
+# taking in account that, depending on host characteristics, libtool
+# may modify these option preferences later in this configure script.
+#
+
+enable_shared=$xc_lt_want_enable_shared
+enable_static=$xc_lt_want_enable_static
+
+#
+# Default behavior is to build PIC objects for shared libraries and
+# non-PIC objects for static libraries.
+#
+
+xc_lt_want_with_pic='default'
+
+#
+# User may have specified PIC preference.
+#
+
+case "x$with_pic" in @%:@ ((
+  xno)
+    xc_lt_want_with_pic='no'
+    ;;
+  xyes)
+    xc_lt_want_with_pic='yes'
+    ;;
+esac
+
+#
+# Default behavior on some systems where building a shared library out
+# of non-PIC compiled objects will fail with following linker error
+# "relocation R_X86_64_32 can not be used when making a shared object"
+# is to build PIC objects even for static libraries. This behavior may
+# be overriden using 'configure --disable-shared --without-pic'.
+#
+
+if test "x$xc_lt_want_with_pic" = 'xdefault'; then
+  case $host_cpu in @%:@ (
+    x86_64 | amd64 | ia64)
+      case $host_os in @%:@ (
+        linux* | freebsd*)
+          xc_lt_want_with_pic='yes'
+          ;;
+      esac
+      ;;
+  esac
+fi
+
+#
+# Make libtool aware of current PIC preference taking in account that,
+# depending on host characteristics, libtool may modify PIC default
+# behavior to fit host system idiosyncrasies later in this script.
+#
+
+with_pic=$xc_lt_want_with_pic
+dnl
+m4_define([$0],[])dnl
+])
+
+
+dnl _XC_LIBTOOL_BODY
+dnl -------------------------------------------------
+dnl Private macro.
+dnl
+dnl This macro performs embedding of libtool code into
+dnl configure script, regardless of libtool version in
+dnl use when generating configure script.
+
+m4_define([_XC_LIBTOOL_BODY],
+[dnl
+## ----------------------- ##
+##  Start of libtool code  ##
+## ----------------------- ##
+m4_ifdef([LT_INIT],
+[dnl
+LT_INIT([win32-dll])
+],[dnl
+AC_LIBTOOL_WIN32_DLL
+AC_PROG_LIBTOOL
+])dnl
+## --------------------- ##
+##  End of libtool code  ##
+## --------------------- ##
+dnl
+m4_define([$0], [])[]dnl
+])
+
+
+dnl _XC_CHECK_LT_BUILD_LIBRARIES
+dnl -------------------------------------------------
+dnl Private macro.
+dnl
+dnl Checks wether libtool shared and static libraries
+dnl are finally built depending on user input, default
+dnl behavior and knowledge that libtool has about host
+dnl characteristics.
+dnl Results stored in following shell variables:
+dnl   xc_lt_build_shared
+dnl   xc_lt_build_static
+
+m4_define([_XC_CHECK_LT_BUILD_LIBRARIES],
+[dnl
+#
+# Verify if finally libtool shared libraries will be built
+#
+
+case "x$enable_shared" in @%:@ ((
+  xyes | xno)
+    xc_lt_build_shared=$enable_shared
+    ;;
+  *)
+    AC_MSG_ERROR([unexpected libtool enable_shared value: $enable_shared])
+    ;;
+esac
+
+#
+# Verify if finally libtool static libraries will be built
+#
+
+case "x$enable_static" in @%:@ ((
+  xyes | xno)
+    xc_lt_build_static=$enable_static
+    ;;
+  *)
+    AC_MSG_ERROR([unexpected libtool enable_static value: $enable_static])
+    ;;
+esac
+dnl
+m4_define([$0],[])dnl
+])
+
+
+dnl _XC_CHECK_LT_SHLIB_USE_VERSION_INFO
+dnl -------------------------------------------------
+dnl Private macro.
+dnl
+dnl Checks if the -version-info linker flag must be
+dnl provided when building libtool shared libraries.
+dnl Result stored in xc_lt_shlib_use_version_info.
+
+m4_define([_XC_CHECK_LT_SHLIB_USE_VERSION_INFO],
+[dnl
+#
+# Verify if libtool shared libraries should be linked using flag -version-info
+#
+
+AC_MSG_CHECKING([whether to build shared libraries with -version-info])
+xc_lt_shlib_use_version_info='yes'
+if test "x$version_type" = 'xnone'; then
+  xc_lt_shlib_use_version_info='no'
+fi
+case $host_os in @%:@ (
+  amigaos*)
+    xc_lt_shlib_use_version_info='yes'
+    ;;
+esac
+AC_MSG_RESULT([$xc_lt_shlib_use_version_info])
+dnl
+m4_define([$0], [])[]dnl
+])
+
+
+dnl _XC_CHECK_LT_SHLIB_USE_NO_UNDEFINED
+dnl -------------------------------------------------
+dnl Private macro.
+dnl
+dnl Checks if the -no-undefined linker flag must be
+dnl provided when building libtool shared libraries.
+dnl Result stored in xc_lt_shlib_use_no_undefined.
+
+m4_define([_XC_CHECK_LT_SHLIB_USE_NO_UNDEFINED],
+[dnl
+#
+# Verify if libtool shared libraries should be linked using flag -no-undefined
+#
+
+AC_MSG_CHECKING([whether to build shared libraries with -no-undefined])
+xc_lt_shlib_use_no_undefined='no'
+if test "x$allow_undefined" = 'xno'; then
+  xc_lt_shlib_use_no_undefined='yes'
+elif test "x$allow_undefined_flag" = 'xunsupported'; then
+  xc_lt_shlib_use_no_undefined='yes'
+fi
+case $host_os in @%:@ (
+  cygwin* | mingw* | pw32* | cegcc* | os2* | aix*)
+    xc_lt_shlib_use_no_undefined='yes'
+    ;;
+esac
+AC_MSG_RESULT([$xc_lt_shlib_use_no_undefined])
+dnl
+m4_define([$0], [])[]dnl
+])
+
+
+dnl _XC_CHECK_LT_SHLIB_USE_MIMPURE_TEXT
+dnl -------------------------------------------------
+dnl Private macro.
+dnl
+dnl Checks if the -mimpure-text linker flag must be
+dnl provided when building libtool shared libraries.
+dnl Result stored in xc_lt_shlib_use_mimpure_text.
+
+m4_define([_XC_CHECK_LT_SHLIB_USE_MIMPURE_TEXT],
+[dnl
+#
+# Verify if libtool shared libraries should be linked using flag -mimpure-text
+#
+
+AC_MSG_CHECKING([whether to build shared libraries with -mimpure-text])
+xc_lt_shlib_use_mimpure_text='no'
+case $host_os in @%:@ (
+  solaris2*)
+    if test "x$GCC" = 'xyes'; then
+      xc_lt_shlib_use_mimpure_text='yes'
+    fi
+    ;;
+esac
+AC_MSG_RESULT([$xc_lt_shlib_use_mimpure_text])
+dnl
+m4_define([$0], [])[]dnl
+])
+
+
+dnl _XC_CHECK_LT_BUILD_WITH_PIC
+dnl -------------------------------------------------
+dnl Private macro.
+dnl
+dnl Checks wether libtool shared and static libraries
+dnl would be built with PIC depending on user input,
+dnl default behavior and knowledge that libtool has
+dnl about host characteristics.
+dnl Results stored in following shell variables:
+dnl   xc_lt_build_shared_with_pic
+dnl   xc_lt_build_static_with_pic
+
+m4_define([_XC_CHECK_LT_BUILD_WITH_PIC],
+[dnl
+#
+# Find out wether libtool libraries would be built wit PIC
+#
+
+case "x$pic_mode" in @%:@ ((((
+  xdefault)
+    xc_lt_build_shared_with_pic='yes'
+    xc_lt_build_static_with_pic='no'
+    ;;
+  xyes)
+    xc_lt_build_shared_with_pic='yes'
+    xc_lt_build_static_with_pic='yes'
+    ;;
+  xno)
+    xc_lt_build_shared_with_pic='no'
+    xc_lt_build_static_with_pic='no'
+    ;;
+  *)
+    xc_lt_build_shared_with_pic='unknown'
+    xc_lt_build_static_with_pic='unknown'
+    AC_MSG_WARN([unexpected libtool pic_mode value: $pic_mode])
+    ;;
+esac
+AC_MSG_CHECKING([whether to build shared libraries with PIC])
+AC_MSG_RESULT([$xc_lt_build_shared_with_pic])
+AC_MSG_CHECKING([whether to build static libraries with PIC])
+AC_MSG_RESULT([$xc_lt_build_static_with_pic])
+dnl
+m4_define([$0],[])dnl
+])
+
+
+dnl _XC_CHECK_LT_BUILD_SINGLE_VERSION
+dnl -------------------------------------------------
+dnl Private macro.
+dnl
+dnl Checks wether a libtool shared or static library
+dnl is finally built exclusively without the other.
+dnl Results stored in following shell variables:
+dnl   xc_lt_build_shared_only
+dnl   xc_lt_build_static_only
+
+m4_define([_XC_CHECK_LT_BUILD_SINGLE_VERSION],
+[dnl
+#
+# Verify if libtool shared libraries will be built while static not built
+#
+
+AC_MSG_CHECKING([whether to build shared libraries only])
+if test "$xc_lt_build_shared" = 'yes' &&
+  test "$xc_lt_build_static" = 'no'; then
+  xc_lt_build_shared_only='yes'
+else
+  xc_lt_build_shared_only='no'
+fi
+AC_MSG_RESULT([$xc_lt_build_shared_only])
+
+#
+# Verify if libtool static libraries will be built while shared not built
+#
+
+AC_MSG_CHECKING([whether to build static libraries only])
+if test "$xc_lt_build_static" = 'yes' &&
+  test "$xc_lt_build_shared" = 'no'; then
+  xc_lt_build_static_only='yes'
+else
+  xc_lt_build_static_only='no'
+fi
+AC_MSG_RESULT([$xc_lt_build_static_only])
+dnl
+m4_define([$0],[])dnl
+])
+
+
+dnl _XC_LIBTOOL_POSTLUDE
+dnl -------------------------------------------------
+dnl Private macro.
+dnl
+dnl Performs several checks related with libtool that
+dnl can not be done unless libtool code has already
+dnl been executed. See individual check descriptions
+dnl for further info.
+
+m4_define([_XC_LIBTOOL_POSTLUDE],
+[dnl
+_XC_CHECK_LT_BUILD_LIBRARIES
+_XC_CHECK_LT_SHLIB_USE_VERSION_INFO
+_XC_CHECK_LT_SHLIB_USE_NO_UNDEFINED
+_XC_CHECK_LT_SHLIB_USE_MIMPURE_TEXT
+_XC_CHECK_LT_BUILD_WITH_PIC
+_XC_CHECK_LT_BUILD_SINGLE_VERSION
+dnl
+m4_define([$0],[])dnl
+])
+
+
+dnl XC_LIBTOOL
+dnl -------------------------------------------------
+dnl Public macro.
+dnl
+dnl This macro embeds libtool machinery into configure
+dnl script, regardless of libtool version, and performs
+dnl several additional checks whose results can be used
+dnl later on.
+dnl
+dnl Usage of this macro ensures that generated configure
+dnl script uses equivalent logic irrespective of autoconf
+dnl or libtool version being used to generate configure
+dnl script.
+dnl
+dnl Results stored in following shell variables:
+dnl   xc_lt_build_shared
+dnl   xc_lt_build_static
+dnl   xc_lt_shlib_use_version_info
+dnl   xc_lt_shlib_use_no_undefined
+dnl   xc_lt_shlib_use_mimpure_text
+dnl   xc_lt_build_shared_with_pic
+dnl   xc_lt_build_static_with_pic
+dnl   xc_lt_build_shared_only
+dnl   xc_lt_build_static_only
+
+AC_DEFUN([XC_LIBTOOL],
+[dnl
+AC_PREREQ([2.50])dnl
+dnl
+AC_BEFORE([$0],[LT_INIT])dnl
+AC_BEFORE([$0],[AC_PROG_LIBTOOL])dnl
+AC_BEFORE([$0],[AC_LIBTOOL_WIN32_DLL])dnl
+dnl
+AC_REQUIRE([XC_CHECK_PATH_SEPARATOR])dnl
+AC_REQUIRE([AC_CANONICAL_HOST])dnl
+AC_REQUIRE([AC_PROG_CC])dnl
+dnl
+_XC_LIBTOOL_PREAMBLE
+_XC_LIBTOOL_BODY
+_XC_LIBTOOL_POSTLUDE
+dnl
+m4_ifdef([AC_LIBTOOL_WIN32_DLL],
+  [m4_undefine([AC_LIBTOOL_WIN32_DLL])])dnl
+m4_ifdef([AC_PROG_LIBTOOL],
+  [m4_undefine([AC_PROG_LIBTOOL])])dnl
+m4_ifdef([LT_INIT],
+  [m4_undefine([LT_INIT])])dnl
+dnl
+m4_define([$0],[])dnl
+])
+
diff --git a/src/c-ares/m4/xc-translit.m4 b/src/c-ares/m4/xc-translit.m4
new file mode 100644
index 000000000..1918f1684
--- /dev/null
+++ b/src/c-ares/m4/xc-translit.m4
@@ -0,0 +1,164 @@
+#---------------------------------------------------------------------------
+#
+# xc-translit.m4
+#
+# Copyright (c) 2011 Daniel Stenberg <daniel@haxx.se>
+#
+# Permission to use, copy, modify, and distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+#
+#---------------------------------------------------------------------------
+
+# File version for 'aclocal' use. Keep it a single number.
+# serial 2
+
+
+dnl XC_SH_TR_SH (expression)
+dnl -------------------------------------------------
+dnl Shell execution time transliteration of 'expression'
+dnl argument, where all non-alfanumeric characters are
+dnl converted to the underscore '_' character.
+dnl Normal shell expansion and substitution takes place
+dnl for given 'expression' at shell execution time before
+dnl transliteration is applied to it.
+
+AC_DEFUN([XC_SH_TR_SH],
+[`echo "$1" | sed 's/[[^a-zA-Z0-9_]]/_/g'`])
+
+
+dnl XC_SH_TR_SH_EX (expression, [extra])
+dnl -------------------------------------------------
+dnl Like XC_SH_TR_SH but transliterating characters
+dnl given in 'extra' argument to lowercase 'p'. For
+dnl example [*+], [*], and [+] are valid 'extra' args.
+
+AC_DEFUN([XC_SH_TR_SH_EX],
+[ifelse([$2], [],
+  [XC_SH_TR_SH([$1])],
+  [`echo "$1" | sed 's/[[$2]]/p/g' | sed 's/[[^a-zA-Z0-9_]]/_/g'`])])
+
+
+dnl XC_M4_TR_SH (expression)
+dnl -------------------------------------------------
+dnl m4 execution time transliteration of 'expression'
+dnl argument, where all non-alfanumeric characters are
+dnl converted to the underscore '_' character.
+
+AC_DEFUN([XC_M4_TR_SH],
+[patsubst(XC_QPATSUBST(XC_QUOTE($1),
+                       [[^a-zA-Z0-9_]], [_]),
+          [\(_\(.*\)_\)], [\2])])
+
+
+dnl XC_M4_TR_SH_EX (expression, [extra])
+dnl -------------------------------------------------
+dnl Like XC_M4_TR_SH but transliterating characters
+dnl given in 'extra' argument to lowercase 'p'. For
+dnl example [*+], [*], and [+] are valid 'extra' args.
+
+AC_DEFUN([XC_M4_TR_SH_EX],
+[ifelse([$2], [],
+  [XC_M4_TR_SH([$1])],
+  [patsubst(XC_QPATSUBST(XC_QPATSUBST(XC_QUOTE($1),
+                                      [[$2]],
+                                      [p]),
+                         [[^a-zA-Z0-9_]], [_]),
+            [\(_\(.*\)_\)], [\2])])])
+
+
+dnl XC_SH_TR_CPP (expression)
+dnl -------------------------------------------------
+dnl Shell execution time transliteration of 'expression'
+dnl argument, where all non-alfanumeric characters are
+dnl converted to the underscore '_' character and alnum
+dnl characters are converted to uppercase.
+dnl Normal shell expansion and substitution takes place
+dnl for given 'expression' at shell execution time before
+dnl transliteration is applied to it.
+
+AC_DEFUN([XC_SH_TR_CPP],
+[`echo "$1" | dnl
+sed 'y/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/' | dnl
+sed 's/[[^A-Z0-9_]]/_/g'`])
+
+
+dnl XC_SH_TR_CPP_EX (expression, [extra])
+dnl -------------------------------------------------
+dnl Like XC_SH_TR_CPP but transliterating characters
+dnl given in 'extra' argument to uppercase 'P'. For
+dnl example [*+], [*], and [+] are valid 'extra' args.
+
+AC_DEFUN([XC_SH_TR_CPP_EX],
+[ifelse([$2], [],
+  [XC_SH_TR_CPP([$1])],
+  [`echo "$1" | dnl
+sed 's/[[$2]]/P/g' | dnl
+sed 'y/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/' | dnl
+sed 's/[[^A-Z0-9_]]/_/g'`])])
+
+
+dnl XC_M4_TR_CPP (expression)
+dnl -------------------------------------------------
+dnl m4 execution time transliteration of 'expression'
+dnl argument, where all non-alfanumeric characters are
+dnl converted to the underscore '_' character and alnum
+dnl characters are converted to uppercase.
+
+AC_DEFUN([XC_M4_TR_CPP],
+[patsubst(XC_QPATSUBST(XC_QTRANSLIT(XC_QUOTE($1),
+                                    [abcdefghijklmnopqrstuvwxyz],
+                                    [ABCDEFGHIJKLMNOPQRSTUVWXYZ]),
+                       [[^A-Z0-9_]], [_]),
+          [\(_\(.*\)_\)], [\2])])
+
+
+dnl XC_M4_TR_CPP_EX (expression, [extra])
+dnl -------------------------------------------------
+dnl Like XC_M4_TR_CPP but transliterating characters
+dnl given in 'extra' argument to uppercase 'P'. For
+dnl example [*+], [*], and [+] are valid 'extra' args.
+
+AC_DEFUN([XC_M4_TR_CPP_EX],
+[ifelse([$2], [],
+  [XC_M4_TR_CPP([$1])],
+  [patsubst(XC_QPATSUBST(XC_QTRANSLIT(XC_QPATSUBST(XC_QUOTE($1),
+                                                   [[$2]],
+                                                   [P]),
+                                      [abcdefghijklmnopqrstuvwxyz],
+                                      [ABCDEFGHIJKLMNOPQRSTUVWXYZ]),
+                         [[^A-Z0-9_]], [_]),
+            [\(_\(.*\)_\)], [\2])])])
+
+
+dnl XC_QUOTE (expression)
+dnl -------------------------------------------------
+dnl Expands to quoted result of 'expression' expansion.
+
+AC_DEFUN([XC_QUOTE],
+[[$@]])
+
+
+dnl XC_QPATSUBST (string, regexp[, repl])
+dnl -------------------------------------------------
+dnl Expands to quoted result of 'patsubst' expansion.
+
+AC_DEFUN([XC_QPATSUBST],
+[XC_QUOTE(patsubst([$1], [$2], [$3]))])
+
+
+dnl XC_QTRANSLIT (string, chars, repl)
+dnl -------------------------------------------------
+dnl Expands to quoted result of 'translit' expansion.
+
+AC_DEFUN([XC_QTRANSLIT],
+[XC_QUOTE(translit([$1], [$2], [$3]))])
+
diff --git a/src/c-ares/m4/xc-val-flgs.m4 b/src/c-ares/m4/xc-val-flgs.m4
new file mode 100644
index 000000000..81d1eac9e
--- /dev/null
+++ b/src/c-ares/m4/xc-val-flgs.m4
@@ -0,0 +1,243 @@
+#---------------------------------------------------------------------------
+#
+# xc-val-flgs.m4
+#
+# Copyright (c) 2013 Daniel Stenberg <daniel@haxx.se>
+#
+# Permission to use, copy, modify, and distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+#
+#---------------------------------------------------------------------------
+
+# serial 1
+
+
+dnl _XC_CHECK_VAR_LIBS
+dnl -------------------------------------------------
+dnl Private macro.
+
+AC_DEFUN([_XC_CHECK_VAR_LIBS], [
+  xc_bad_var_libs=no
+  for xc_word in $LIBS; do
+    case "$xc_word" in
+      -l* | --library=*)
+        :
+        ;;
+      *)
+        xc_bad_var_libs=yes
+        ;;
+    esac
+  done
+  if test $xc_bad_var_libs = yes; then
+    AC_MSG_NOTICE([using LIBS: $LIBS])
+    AC_MSG_NOTICE([LIBS error: LIBS may only be used to specify libraries (-lname).])
+  fi
+])
+
+
+dnl _XC_CHECK_VAR_LDFLAGS
+dnl -------------------------------------------------
+dnl Private macro.
+
+AC_DEFUN([_XC_CHECK_VAR_LDFLAGS], [
+  xc_bad_var_ldflags=no
+  for xc_word in $LDFLAGS; do
+    case "$xc_word" in
+      -D*)
+        xc_bad_var_ldflags=yes
+        ;;
+      -U*)
+        xc_bad_var_ldflags=yes
+        ;;
+      -I*)
+        xc_bad_var_ldflags=yes
+        ;;
+      -l* | --library=*)
+        xc_bad_var_ldflags=yes
+        ;;
+    esac
+  done
+  if test $xc_bad_var_ldflags = yes; then
+    AC_MSG_NOTICE([using LDFLAGS: $LDFLAGS])
+    xc_bad_var_msg="LDFLAGS error: LDFLAGS may only be used to specify linker flags, not"
+    for xc_word in $LDFLAGS; do
+      case "$xc_word" in
+        -D*)
+          AC_MSG_NOTICE([$xc_bad_var_msg macro definitions. Use CPPFLAGS for: $xc_word])
+          ;;
+        -U*)
+          AC_MSG_NOTICE([$xc_bad_var_msg macro suppressions. Use CPPFLAGS for: $xc_word])
+          ;;
+        -I*)
+          AC_MSG_NOTICE([$xc_bad_var_msg include directories. Use CPPFLAGS for: $xc_word])
+          ;;
+        -l* | --library=*)
+          AC_MSG_NOTICE([$xc_bad_var_msg libraries. Use LIBS for: $xc_word])
+          ;;
+      esac
+    done
+  fi
+])
+
+
+dnl _XC_CHECK_VAR_CPPFLAGS
+dnl -------------------------------------------------
+dnl Private macro.
+
+AC_DEFUN([_XC_CHECK_VAR_CPPFLAGS], [
+  xc_bad_var_cppflags=no
+  for xc_word in $CPPFLAGS; do
+    case "$xc_word" in
+      -rpath*)
+        xc_bad_var_cppflags=yes
+        ;;
+      -L* | --library-path=*)
+        xc_bad_var_cppflags=yes
+        ;;
+      -l* | --library=*)
+        xc_bad_var_cppflags=yes
+        ;;
+    esac
+  done
+  if test $xc_bad_var_cppflags = yes; then
+    AC_MSG_NOTICE([using CPPFLAGS: $CPPFLAGS])
+    xc_bad_var_msg="CPPFLAGS error: CPPFLAGS may only be used to specify C preprocessor flags, not"
+    for xc_word in $CPPFLAGS; do
+      case "$xc_word" in
+        -rpath*)
+          AC_MSG_NOTICE([$xc_bad_var_msg library runtime directories. Use LDFLAGS for: $xc_word])
+          ;;
+        -L* | --library-path=*)
+          AC_MSG_NOTICE([$xc_bad_var_msg library directories. Use LDFLAGS for: $xc_word])
+          ;;
+        -l* | --library=*)
+          AC_MSG_NOTICE([$xc_bad_var_msg libraries. Use LIBS for: $xc_word])
+          ;;
+      esac
+    done
+  fi
+])
+
+
+dnl _XC_CHECK_VAR_CFLAGS
+dnl -------------------------------------------------
+dnl Private macro.
+
+AC_DEFUN([_XC_CHECK_VAR_CFLAGS], [
+  xc_bad_var_cflags=no
+  for xc_word in $CFLAGS; do
+    case "$xc_word" in
+      -D*)
+        xc_bad_var_cflags=yes
+        ;;
+      -U*)
+        xc_bad_var_cflags=yes
+        ;;
+      -I*)
+        xc_bad_var_cflags=yes
+        ;;
+      -rpath*)
+        xc_bad_var_cflags=yes
+        ;;
+      -L* | --library-path=*)
+        xc_bad_var_cflags=yes
+        ;;
+      -l* | --library=*)
+        xc_bad_var_cflags=yes
+        ;;
+    esac
+  done
+  if test $xc_bad_var_cflags = yes; then
+    AC_MSG_NOTICE([using CFLAGS: $CFLAGS])
+    xc_bad_var_msg="CFLAGS error: CFLAGS may only be used to specify C compiler flags, not"
+    for xc_word in $CFLAGS; do
+      case "$xc_word" in
+        -D*)
+          AC_MSG_NOTICE([$xc_bad_var_msg macro definitions. Use CPPFLAGS for: $xc_word])
+          ;;
+        -U*)
+          AC_MSG_NOTICE([$xc_bad_var_msg macro suppressions. Use CPPFLAGS for: $xc_word])
+          ;;
+        -I*)
+          AC_MSG_NOTICE([$xc_bad_var_msg include directories. Use CPPFLAGS for: $xc_word])
+          ;;
+        -rpath*)
+          AC_MSG_NOTICE([$xc_bad_var_msg library runtime directories. Use LDFLAGS for: $xc_word])
+          ;;
+        -L* | --library-path=*)
+          AC_MSG_NOTICE([$xc_bad_var_msg library directories. Use LDFLAGS for: $xc_word])
+          ;;
+        -l* | --library=*)
+          AC_MSG_NOTICE([$xc_bad_var_msg libraries. Use LIBS for: $xc_word])
+          ;;
+      esac
+    done
+  fi
+])
+
+
+dnl XC_CHECK_USER_FLAGS
+dnl -------------------------------------------------
+dnl Public macro.
+dnl
+dnl Performs some sanity checks for LIBS, LDFLAGS,
+dnl CPPFLAGS and CFLAGS values that the user might
+dnl have set. When checks fails, user is noticed
+dnl about errors detected in all of them and script
+dnl execution is halted.
+dnl
+dnl Intended to be used early in configure script.
+
+AC_DEFUN([XC_CHECK_USER_FLAGS], [
+  AC_PREREQ([2.50])dnl
+  AC_BEFORE([$0],[XC_CHECK_PROG_CC])dnl
+  dnl check order below matters
+  _XC_CHECK_VAR_LIBS
+  _XC_CHECK_VAR_LDFLAGS
+  _XC_CHECK_VAR_CPPFLAGS
+  _XC_CHECK_VAR_CFLAGS
+  if test $xc_bad_var_libs = yes ||
+     test $xc_bad_var_cflags = yes ||
+     test $xc_bad_var_ldflags = yes ||
+     test $xc_bad_var_cppflags = yes; then
+     AC_MSG_ERROR([Can not continue. Fix errors mentioned immediately above this line.])
+  fi
+])
+
+
+dnl XC_CHECK_BUILD_FLAGS
+dnl -------------------------------------------------
+dnl Public macro.
+dnl
+dnl Performs some sanity checks for LIBS, LDFLAGS,
+dnl CPPFLAGS and CFLAGS values that the configure
+dnl script might have set. When checks fails, user
+dnl is noticed about errors detected in all of them
+dnl but script continues execution.
+dnl
+dnl Intended to be used very late in configure script.
+
+AC_DEFUN([XC_CHECK_BUILD_FLAGS], [
+  AC_PREREQ([2.50])dnl
+  dnl check order below matters
+  _XC_CHECK_VAR_LIBS
+  _XC_CHECK_VAR_LDFLAGS
+  _XC_CHECK_VAR_CPPFLAGS
+  _XC_CHECK_VAR_CFLAGS
+  if test $xc_bad_var_libs = yes ||
+     test $xc_bad_var_cflags = yes ||
+     test $xc_bad_var_ldflags = yes ||
+     test $xc_bad_var_cppflags = yes; then
+     AC_MSG_WARN([Continuing even with errors mentioned immediately above this line.])
+  fi
+])
+
diff --git a/src/c-ares/m4/zz40-xc-ovr.m4 b/src/c-ares/m4/zz40-xc-ovr.m4
new file mode 100644
index 000000000..0e3b1cba6
--- /dev/null
+++ b/src/c-ares/m4/zz40-xc-ovr.m4
@@ -0,0 +1,668 @@
+#---------------------------------------------------------------------------
+#
+# zz40-xc-ovr.m4
+#
+# Copyright (c) 2013 Daniel Stenberg <daniel@haxx.se>
+#
+# Permission to use, copy, modify, and distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+#
+#---------------------------------------------------------------------------
+
+# serial 1
+
+
+dnl The funny name of this file is intentional in order to make it
+dnl sort alphabetically after any libtool, autoconf or automake
+dnl provided .m4 macro file that might get copied into this same
+dnl subdirectory. This allows that macro (re)definitions from this
+dnl file may override those provided in other files.
+
+
+dnl Version macros
+dnl -------------------------------------------------
+dnl Public macros.
+
+m4_define([XC_CONFIGURE_PREAMBLE_VER_MAJOR],[1])dnl
+m4_define([XC_CONFIGURE_PREAMBLE_VER_MINOR],[0])dnl
+
+
+dnl _XC_CFG_PRE_PREAMBLE
+dnl -------------------------------------------------
+dnl Private macro.
+
+AC_DEFUN([_XC_CFG_PRE_PREAMBLE],
+[
+## -------------------------------- ##
+@%:@@%:@  [XC_CONFIGURE_PREAMBLE] ver: []dnl
+XC_CONFIGURE_PREAMBLE_VER_MAJOR.[]dnl
+XC_CONFIGURE_PREAMBLE_VER_MINOR  ##
+## -------------------------------- ##
+
+xc_configure_preamble_ver_major='XC_CONFIGURE_PREAMBLE_VER_MAJOR'
+xc_configure_preamble_ver_minor='XC_CONFIGURE_PREAMBLE_VER_MINOR'
+
+#
+# Set IFS to space, tab and newline.
+#
+
+xc_space=' '
+xc_tab='	'
+xc_newline='
+'
+IFS="$xc_space$xc_tab$xc_newline"
+
+#
+# Set internationalization behavior variables.
+#
+
+LANG='C'
+LC_ALL='C'
+LANGUAGE='C'
+export LANG
+export LC_ALL
+export LANGUAGE
+
+#
+# Some useful variables.
+#
+
+xc_msg_warn='configure: WARNING:'
+xc_msg_abrt='Can not continue.'
+xc_msg_err='configure: error:'
+])
+
+
+dnl _XC_CFG_PRE_BASIC_CHK_CMD_ECHO
+dnl -------------------------------------------------
+dnl Private macro.
+dnl
+dnl Emits shell code that verifies that 'echo' command
+dnl is available, otherwise aborts execution.
+
+AC_DEFUN([_XC_CFG_PRE_BASIC_CHK_CMD_ECHO],
+[dnl
+AC_REQUIRE([_XC_CFG_PRE_PREAMBLE])dnl
+#
+# Verify that 'echo' command is available, otherwise abort.
+#
+
+xc_tst_str='unknown'
+(`echo "$xc_tst_str" >/dev/null 2>&1`) && xc_tst_str='success'
+case "x$xc_tst_str" in @%:@ ((
+  xsuccess)
+    :
+    ;;
+  *)
+    # Try built-in echo, and fail.
+    echo "$xc_msg_err 'echo' command not found. $xc_msg_abrt" >&2
+    exit 1
+    ;;
+esac
+])
+
+
+dnl _XC_CFG_PRE_BASIC_CHK_CMD_TEST
+dnl -------------------------------------------------
+dnl Private macro.
+dnl
+dnl Emits shell code that verifies that 'test' command
+dnl is available, otherwise aborts execution.
+
+AC_DEFUN([_XC_CFG_PRE_BASIC_CHK_CMD_TEST],
+[dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_CMD_ECHO])dnl
+#
+# Verify that 'test' command is available, otherwise abort.
+#
+
+xc_tst_str='unknown'
+(`test -n "$xc_tst_str" >/dev/null 2>&1`) && xc_tst_str='success'
+case "x$xc_tst_str" in @%:@ ((
+  xsuccess)
+    :
+    ;;
+  *)
+    echo "$xc_msg_err 'test' command not found. $xc_msg_abrt" >&2
+    exit 1
+    ;;
+esac
+])
+
+
+dnl _XC_CFG_PRE_BASIC_CHK_VAR_PATH
+dnl -------------------------------------------------
+dnl Private macro.
+dnl
+dnl Emits shell code that verifies that 'PATH' variable
+dnl is set, otherwise aborts execution.
+
+AC_DEFUN([_XC_CFG_PRE_BASIC_CHK_VAR_PATH],
+[dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_CMD_TEST])dnl
+#
+# Verify that 'PATH' variable is set, otherwise abort.
+#
+
+xc_tst_str='unknown'
+(`test -n "$PATH" >/dev/null 2>&1`) && xc_tst_str='success'
+case "x$xc_tst_str" in @%:@ ((
+  xsuccess)
+    :
+    ;;
+  *)
+    echo "$xc_msg_err 'PATH' variable not set. $xc_msg_abrt" >&2
+    exit 1
+    ;;
+esac
+])
+
+
+dnl _XC_CFG_PRE_BASIC_CHK_CMD_EXPR
+dnl -------------------------------------------------
+dnl Private macro.
+dnl
+dnl Emits shell code that verifies that 'expr' command
+dnl is available, otherwise aborts execution.
+
+AC_DEFUN([_XC_CFG_PRE_BASIC_CHK_CMD_EXPR],
+[dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_VAR_PATH])dnl
+#
+# Verify that 'expr' command is available, otherwise abort.
+#
+
+xc_tst_str='unknown'
+xc_tst_str=`expr "$xc_tst_str" : '.*' 2>/dev/null`
+case "x$xc_tst_str" in @%:@ ((
+  x7)
+    :
+    ;;
+  *)
+    echo "$xc_msg_err 'expr' command not found. $xc_msg_abrt" >&2
+    exit 1
+    ;;
+esac
+])
+
+
+dnl _XC_CFG_PRE_BASIC_CHK_UTIL_SED
+dnl -------------------------------------------------
+dnl Private macro.
+dnl
+dnl Emits shell code that verifies that 'sed' utility
+dnl is found within 'PATH', otherwise aborts execution.
+dnl
+dnl This 'sed' is required in order to allow configure
+dnl script bootstrapping itself. No fancy testing for a
+dnl proper 'sed' this early, that should be done later.
+
+AC_DEFUN([_XC_CFG_PRE_BASIC_CHK_UTIL_SED],
+[dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_VAR_PATH])dnl
+#
+# Verify that 'sed' utility is found within 'PATH', otherwise abort.
+#
+
+xc_tst_str='unknown'
+xc_tst_str=`echo "$xc_tst_str" 2>/dev/null \
+  | sed -e 's:unknown:success:' 2>/dev/null`
+case "x$xc_tst_str" in @%:@ ((
+  xsuccess)
+    :
+    ;;
+  *)
+    echo "$xc_msg_err 'sed' utility not found in 'PATH'. $xc_msg_abrt" >&2
+    exit 1
+    ;;
+esac
+])
+
+
+dnl _XC_CFG_PRE_BASIC_CHK_UTIL_GREP
+dnl -------------------------------------------------
+dnl Private macro.
+dnl
+dnl Emits shell code that verifies that 'grep' utility
+dnl is found within 'PATH', otherwise aborts execution.
+dnl
+dnl This 'grep' is required in order to allow configure
+dnl script bootstrapping itself. No fancy testing for a
+dnl proper 'grep' this early, that should be done later.
+
+AC_DEFUN([_XC_CFG_PRE_BASIC_CHK_UTIL_GREP],
+[dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_VAR_PATH])dnl
+#
+# Verify that 'grep' utility is found within 'PATH', otherwise abort.
+#
+
+xc_tst_str='unknown'
+(`echo "$xc_tst_str" 2>/dev/null \
+  | grep 'unknown' >/dev/null 2>&1`) && xc_tst_str='success'
+case "x$xc_tst_str" in @%:@ ((
+  xsuccess)
+    :
+    ;;
+  *)
+    echo "$xc_msg_err 'grep' utility not found in 'PATH'. $xc_msg_abrt" >&2
+    exit 1
+    ;;
+esac
+])
+
+
+dnl _XC_CFG_PRE_BASIC_CHK_UTIL_TR
+dnl -------------------------------------------------
+dnl Private macro.
+dnl
+dnl Emits shell code that verifies that 'tr' utility
+dnl is found within 'PATH', otherwise aborts execution.
+
+AC_DEFUN([_XC_CFG_PRE_BASIC_CHK_UTIL_TR],
+[dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_VAR_PATH])dnl
+#
+# Verify that 'tr' utility is found within 'PATH', otherwise abort.
+#
+
+xc_tst_str="${xc_tab}98s7u6c5c4e3s2s10"
+xc_tst_str=`echo "$xc_tst_str" 2>/dev/null \
+  | tr -d "0123456789$xc_tab" 2>/dev/null`
+case "x$xc_tst_str" in @%:@ ((
+  xsuccess)
+    :
+    ;;
+  *)
+    echo "$xc_msg_err 'tr' utility not found in 'PATH'. $xc_msg_abrt" >&2
+    exit 1
+    ;;
+esac
+])
+
+
+dnl _XC_CFG_PRE_BASIC_CHK_UTIL_WC
+dnl -------------------------------------------------
+dnl Private macro.
+dnl
+dnl Emits shell code that verifies that 'wc' utility
+dnl is found within 'PATH', otherwise aborts execution.
+
+AC_DEFUN([_XC_CFG_PRE_BASIC_CHK_UTIL_WC],
+[dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_UTIL_TR])dnl
+#
+# Verify that 'wc' utility is found within 'PATH', otherwise abort.
+#
+
+xc_tst_str='unknown unknown unknown unknown'
+xc_tst_str=`echo "$xc_tst_str" 2>/dev/null \
+  | wc -w 2>/dev/null | tr -d "$xc_space$xc_tab" 2>/dev/null`
+case "x$xc_tst_str" in @%:@ ((
+  x4)
+    :
+    ;;
+  *)
+    echo "$xc_msg_err 'wc' utility not found in 'PATH'. $xc_msg_abrt" >&2
+    exit 1
+    ;;
+esac
+])
+
+
+dnl _XC_CFG_PRE_BASIC_CHK_UTIL_CAT
+dnl -------------------------------------------------
+dnl Private macro.
+dnl
+dnl Emits shell code that verifies that 'cat' utility
+dnl is found within 'PATH', otherwise aborts execution.
+
+AC_DEFUN([_XC_CFG_PRE_BASIC_CHK_UTIL_CAT],
+[dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_UTIL_WC])dnl
+#
+# Verify that 'cat' utility is found within 'PATH', otherwise abort.
+#
+
+xc_tst_str='unknown'
+xc_tst_str=`cat <<_EOT 2>/dev/null \
+  | wc -l 2>/dev/null | tr -d "$xc_space$xc_tab" 2>/dev/null
+unknown
+unknown
+unknown
+_EOT`
+case "x$xc_tst_str" in @%:@ ((
+  x3)
+    :
+    ;;
+  *)
+    echo "$xc_msg_err 'cat' utility not found in 'PATH'. $xc_msg_abrt" >&2
+    exit 1
+    ;;
+esac
+])
+
+
+dnl _XC_CFG_PRE_CHECK_PATH_SEPARATOR
+dnl -------------------------------------------------
+dnl Private macro.
+dnl
+dnl Emits shell code that computes the path separator
+dnl and stores the result in 'PATH_SEPARATOR', unless
+dnl the user has already set it with a non-empty value.
+dnl
+dnl This path separator is the symbol used to separate
+dnl or diferentiate paths inside the 'PATH' environment
+dnl variable.
+dnl
+dnl Non-empty user provided 'PATH_SEPARATOR' always
+dnl overrides the auto-detected one.
+
+AC_DEFUN([_XC_CFG_PRE_CHECK_PATH_SEPARATOR],
+[dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_CMD_EXPR])dnl
+#
+# Auto-detect and set 'PATH_SEPARATOR', unless it is already non-empty set.
+#
+
+# Directory count in 'PATH' when using a colon separator.
+xc_tst_dirs_col='x'
+xc_tst_prev_IFS=$IFS; IFS=':'
+for xc_tst_dir in $PATH; do
+  IFS=$xc_tst_prev_IFS
+  xc_tst_dirs_col="x$xc_tst_dirs_col"
+done
+IFS=$xc_tst_prev_IFS
+xc_tst_dirs_col=`expr "$xc_tst_dirs_col" : '.*'`
+
+# Directory count in 'PATH' when using a semicolon separator.
+xc_tst_dirs_sem='x'
+xc_tst_prev_IFS=$IFS; IFS=';'
+for xc_tst_dir in $PATH; do
+  IFS=$xc_tst_prev_IFS
+  xc_tst_dirs_sem="x$xc_tst_dirs_sem"
+done
+IFS=$xc_tst_prev_IFS
+xc_tst_dirs_sem=`expr "$xc_tst_dirs_sem" : '.*'`
+
+if test $xc_tst_dirs_sem -eq $xc_tst_dirs_col; then
+  # When both counting methods give the same result we do not want to
+  # chose one over the other, and consider auto-detection not possible.
+  if test -z "$PATH_SEPARATOR"; then
+    # Stop dead until user provides 'PATH_SEPARATOR' definition.
+    echo "$xc_msg_err 'PATH_SEPARATOR' variable not set. $xc_msg_abrt" >&2
+    exit 1
+  fi
+else
+  # Separator with the greater directory count is the auto-detected one.
+  if test $xc_tst_dirs_sem -gt $xc_tst_dirs_col; then
+    xc_tst_auto_separator=';'
+  else
+    xc_tst_auto_separator=':'
+  fi
+  if test -z "$PATH_SEPARATOR"; then
+    # Simply use the auto-detected one when not already set.
+    PATH_SEPARATOR=$xc_tst_auto_separator
+  elif test "x$PATH_SEPARATOR" != "x$xc_tst_auto_separator"; then
+    echo "$xc_msg_warn 'PATH_SEPARATOR' does not match auto-detected one." >&2
+  fi
+fi
+xc_PATH_SEPARATOR=$PATH_SEPARATOR
+AC_SUBST([PATH_SEPARATOR])dnl
+])
+
+
+dnl _XC_CFG_PRE_POSTLUDE
+dnl -------------------------------------------------
+dnl Private macro.
+
+AC_DEFUN([_XC_CFG_PRE_POSTLUDE],
+[dnl
+AC_REQUIRE([_XC_CFG_PRE_PREAMBLE])dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_CMD_ECHO])dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_CMD_TEST])dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_VAR_PATH])dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_CMD_EXPR])dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_UTIL_SED])dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_UTIL_GREP])dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_UTIL_TR])dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_UTIL_WC])dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_UTIL_CAT])dnl
+AC_REQUIRE([_XC_CFG_PRE_CHECK_PATH_SEPARATOR])dnl
+dnl
+xc_configure_preamble_result='yes'
+])
+
+
+dnl XC_CONFIGURE_PREAMBLE
+dnl -------------------------------------------------
+dnl Public macro.
+dnl
+dnl This macro emits shell code which does some
+dnl very basic checks related with the availability
+dnl of some commands and utilities needed to allow
+dnl configure script bootstrapping itself when using
+dnl these to figure out other settings. Also emits
+dnl code that performs PATH_SEPARATOR auto-detection
+dnl and sets its value unless it is already set with
+dnl a non-empty value.
+dnl
+dnl These basic checks are intended to be placed and
+dnl executed as early as possible in the resulting
+dnl configure script, and as such these must be pure
+dnl and portable shell code.
+dnl
+dnl This macro may be used directly, or indirectly
+dnl when using other macros that AC_REQUIRE it such
+dnl as XC_CHECK_PATH_SEPARATOR.
+dnl
+dnl Currently the mechanism used to ensure that this
+dnl macro expands early enough in generated configure
+dnl script is making it override autoconf and libtool
+dnl PATH_SEPARATOR check.
+
+AC_DEFUN([XC_CONFIGURE_PREAMBLE],
+[dnl
+AC_PREREQ([2.50])dnl
+dnl
+AC_BEFORE([$0],[_XC_CFG_PRE_PREAMBLE])dnl
+AC_BEFORE([$0],[_XC_CFG_PRE_BASIC_CHK_CMD_ECHO])dnl
+AC_BEFORE([$0],[_XC_CFG_PRE_BASIC_CHK_CMD_TEST])dnl
+AC_BEFORE([$0],[_XC_CFG_PRE_BASIC_CHK_VAR_PATH])dnl
+AC_BEFORE([$0],[_XC_CFG_PRE_BASIC_CHK_CMD_EXPR])dnl
+AC_BEFORE([$0],[_XC_CFG_PRE_BASIC_CHK_UTIL_SED])dnl
+AC_BEFORE([$0],[_XC_CFG_PRE_BASIC_CHK_UTIL_GREP])dnl
+AC_BEFORE([$0],[_XC_CFG_PRE_BASIC_CHK_UTIL_TR])dnl
+AC_BEFORE([$0],[_XC_CFG_PRE_BASIC_CHK_UTIL_WC])dnl
+AC_BEFORE([$0],[_XC_CFG_PRE_BASIC_CHK_UTIL_CAT])dnl
+AC_BEFORE([$0],[_XC_CFG_PRE_CHECK_PATH_SEPARATOR])dnl
+AC_BEFORE([$0],[_XC_CFG_PRE_POSTLUDE])dnl
+dnl
+AC_BEFORE([$0],[AC_CHECK_TOOL])dnl
+AC_BEFORE([$0],[AC_CHECK_PROG])dnl
+AC_BEFORE([$0],[AC_CHECK_TOOLS])dnl
+AC_BEFORE([$0],[AC_CHECK_PROGS])dnl
+dnl
+AC_BEFORE([$0],[AC_PATH_TOOL])dnl
+AC_BEFORE([$0],[AC_PATH_PROG])dnl
+AC_BEFORE([$0],[AC_PATH_PROGS])dnl
+dnl
+AC_BEFORE([$0],[AC_PROG_SED])dnl
+AC_BEFORE([$0],[AC_PROG_GREP])dnl
+AC_BEFORE([$0],[AC_PROG_LN_S])dnl
+AC_BEFORE([$0],[AC_PROG_MKDIR_P])dnl
+AC_BEFORE([$0],[AC_PROG_INSTALL])dnl
+AC_BEFORE([$0],[AC_PROG_MAKE_SET])dnl
+AC_BEFORE([$0],[AC_PROG_LIBTOOL])dnl
+dnl
+AC_BEFORE([$0],[LT_INIT])dnl
+AC_BEFORE([$0],[AM_INIT_AUTOMAKE])dnl
+AC_BEFORE([$0],[AC_LIBTOOL_WIN32_DLL])dnl
+dnl
+AC_REQUIRE([_XC_CFG_PRE_PREAMBLE])dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_CMD_ECHO])dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_CMD_TEST])dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_VAR_PATH])dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_CMD_EXPR])dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_UTIL_SED])dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_UTIL_GREP])dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_UTIL_TR])dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_UTIL_WC])dnl
+AC_REQUIRE([_XC_CFG_PRE_BASIC_CHK_UTIL_CAT])dnl
+AC_REQUIRE([_XC_CFG_PRE_CHECK_PATH_SEPARATOR])dnl
+AC_REQUIRE([_XC_CFG_PRE_POSTLUDE])dnl
+dnl
+m4_pattern_forbid([^_*XC])dnl
+m4_define([$0],[])dnl
+])
+
+
+dnl Override autoconf and libtool PATH_SEPARATOR check
+dnl -------------------------------------------------
+dnl Macros overriding.
+dnl
+dnl This is done to ensure that the same check is
+dnl used across different autoconf versions and to
+dnl allow expansion of XC_CONFIGURE_PREAMBLE macro
+dnl early enough in the generated configure script.
+
+dnl
+dnl Override when using autoconf 2.53 and newer.
+dnl
+
+m4_ifdef([_AS_PATH_SEPARATOR_PREPARE],
+[dnl
+m4_undefine([_AS_PATH_SEPARATOR_PREPARE])dnl
+m4_defun([_AS_PATH_SEPARATOR_PREPARE],
+[dnl
+AC_REQUIRE([XC_CONFIGURE_PREAMBLE])dnl
+m4_define([$0],[])dnl
+])dnl
+])
+
+dnl
+dnl Override when using autoconf 2.50 to 2.52
+dnl
+
+m4_ifdef([_AC_INIT_PREPARE_FS_SEPARATORS],
+[dnl
+m4_undefine([_AC_INIT_PREPARE_FS_SEPARATORS])dnl
+m4_defun([_AC_INIT_PREPARE_FS_SEPARATORS],
+[dnl
+AC_REQUIRE([XC_CONFIGURE_PREAMBLE])dnl
+ac_path_separator=$PATH_SEPARATOR
+m4_define([$0],[])dnl
+])dnl
+])
+
+dnl
+dnl Override when using libtool 1.4.2
+dnl
+
+m4_ifdef([_LT_AC_LIBTOOL_SYS_PATH_SEPARATOR],
+[dnl
+m4_undefine([_LT_AC_LIBTOOL_SYS_PATH_SEPARATOR])dnl
+m4_defun([_LT_AC_LIBTOOL_SYS_PATH_SEPARATOR],
+[dnl
+AC_REQUIRE([XC_CONFIGURE_PREAMBLE])dnl
+lt_cv_sys_path_separator=$PATH_SEPARATOR
+m4_define([$0],[])dnl
+])dnl
+])
+
+
+dnl XC_CHECK_PATH_SEPARATOR
+dnl -------------------------------------------------
+dnl Public macro.
+dnl
+dnl Usage of this macro ensures that generated configure
+dnl script uses the same PATH_SEPARATOR check irrespective
+dnl of autoconf or libtool version being used to generate
+dnl configure script.
+dnl
+dnl Emits shell code that computes the path separator
+dnl and stores the result in 'PATH_SEPARATOR', unless
+dnl the user has already set it with a non-empty value.
+dnl
+dnl This path separator is the symbol used to separate
+dnl or diferentiate paths inside the 'PATH' environment
+dnl variable.
+dnl
+dnl Non-empty user provided 'PATH_SEPARATOR' always
+dnl overrides the auto-detected one.
+dnl
+dnl Strictly speaking the check is done in two steps. The
+dnl first, which does the actual check, takes place in
+dnl XC_CONFIGURE_PREAMBLE macro and happens very early in
+dnl generated configure script. The second one shows and
+dnl logs the result of the check into config.log at a later
+dnl configure stage. Placement of this second stage in
+dnl generated configure script will be done where first
+dnl direct or indirect usage of this macro happens.
+
+AC_DEFUN([XC_CHECK_PATH_SEPARATOR],
+[dnl
+AC_PREREQ([2.50])dnl
+dnl
+AC_BEFORE([$0],[AC_CHECK_TOOL])dnl
+AC_BEFORE([$0],[AC_CHECK_PROG])dnl
+AC_BEFORE([$0],[AC_CHECK_TOOLS])dnl
+AC_BEFORE([$0],[AC_CHECK_PROGS])dnl
+dnl
+AC_BEFORE([$0],[AC_PATH_TOOL])dnl
+AC_BEFORE([$0],[AC_PATH_PROG])dnl
+AC_BEFORE([$0],[AC_PATH_PROGS])dnl
+dnl
+AC_BEFORE([$0],[AC_PROG_SED])dnl
+AC_BEFORE([$0],[AC_PROG_GREP])dnl
+AC_BEFORE([$0],[AC_PROG_LN_S])dnl
+AC_BEFORE([$0],[AC_PROG_MKDIR_P])dnl
+AC_BEFORE([$0],[AC_PROG_INSTALL])dnl
+AC_BEFORE([$0],[AC_PROG_MAKE_SET])dnl
+AC_BEFORE([$0],[AC_PROG_LIBTOOL])dnl
+dnl
+AC_BEFORE([$0],[LT_INIT])dnl
+AC_BEFORE([$0],[AM_INIT_AUTOMAKE])dnl
+AC_BEFORE([$0],[AC_LIBTOOL_WIN32_DLL])dnl
+dnl
+AC_REQUIRE([XC_CONFIGURE_PREAMBLE])dnl
+dnl
+#
+# Check that 'XC_CONFIGURE_PREAMBLE' has already run.
+#
+
+if test -z "$xc_configure_preamble_result"; then
+  AC_MSG_ERROR([xc_configure_preamble_result not set (internal problem)])
+fi
+
+#
+# Check that 'PATH_SEPARATOR' has already been set.
+#
+
+if test -z "$xc_PATH_SEPARATOR"; then
+  AC_MSG_ERROR([xc_PATH_SEPARATOR not set (internal problem)])
+fi
+if test -z "$PATH_SEPARATOR"; then
+  AC_MSG_ERROR([PATH_SEPARATOR not set (internal or config.site problem)])
+fi
+AC_MSG_CHECKING([for path separator])
+AC_MSG_RESULT([$PATH_SEPARATOR])
+if test "x$PATH_SEPARATOR" != "x$xc_PATH_SEPARATOR"; then
+  AC_MSG_CHECKING([for initial path separator])
+  AC_MSG_RESULT([$xc_PATH_SEPARATOR])
+  AC_MSG_ERROR([path separator mismatch (internal or config.site problem)])
+fi
+dnl
+m4_pattern_forbid([^_*XC])dnl
+m4_define([$0],[])dnl
+])
+
diff --git a/src/c-ares/m4/zz50-xc-ovr.m4 b/src/c-ares/m4/zz50-xc-ovr.m4
new file mode 100644
index 000000000..7e9ae592e
--- /dev/null
+++ b/src/c-ares/m4/zz50-xc-ovr.m4
@@ -0,0 +1,60 @@
+#---------------------------------------------------------------------------
+#
+# zz50-xc-ovr.m4
+#
+# Copyright (c) 2011 Daniel Stenberg <daniel@haxx.se>
+#
+# Permission to use, copy, modify, and distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+#
+#---------------------------------------------------------------------------
+
+# serial 1
+
+
+dnl The funny name of this file is intentional in order to make it
+dnl sort alphabetically after any libtool, autoconf or automake
+dnl provided .m4 macro file that might get copied into this same
+dnl subdirectory. This allows that macro (re)definitions from this
+dnl file may override those provided in other files.
+
+
+dnl Override some language related macros
+dnl -------------------------------------------------
+dnl This is done to prevent Libtool 1.5.X from doing
+dnl unnecesary C++, Fortran and Java tests when only
+dnl using C language and reduce resulting configure
+dnl script by nearly 300 Kb.
+
+m4_ifdef([AC_LIBTOOL_LANG_CXX_CONFIG],
+  [m4_undefine([AC_LIBTOOL_LANG_CXX_CONFIG])])
+m4_define([AC_LIBTOOL_LANG_CXX_CONFIG],[:])
+
+m4_ifdef([AC_LIBTOOL_LANG_F77_CONFIG],
+  [m4_undefine([AC_LIBTOOL_LANG_F77_CONFIG])])
+m4_define([AC_LIBTOOL_LANG_F77_CONFIG],[:])
+
+m4_ifdef([AC_LIBTOOL_LANG_GCJ_CONFIG],
+  [m4_undefine([AC_LIBTOOL_LANG_GCJ_CONFIG])])
+m4_define([AC_LIBTOOL_LANG_GCJ_CONFIG],[:])
+
+
+dnl XC_OVR_ZZ50
+dnl -------------------------------------------------
+dnl Placing a call to this macro in configure.ac will
+dnl make macros in this file visible to other macros
+dnl used for same configure script, overriding those
+dnl provided elsewhere.
+
+AC_DEFUN([XC_OVR_ZZ50],
+  [AC_BEFORE([$0],[AC_PROG_LIBTOOL])])
+
diff --git a/src/c-ares/m4/zz60-xc-ovr.m4 b/src/c-ares/m4/zz60-xc-ovr.m4
new file mode 100644
index 000000000..959f11883
--- /dev/null
+++ b/src/c-ares/m4/zz60-xc-ovr.m4
@@ -0,0 +1,64 @@
+#---------------------------------------------------------------------------
+#
+# zz60-xc-ovr.m4
+#
+# Copyright (c) 2013 Daniel Stenberg <daniel@haxx.se>
+#
+# Permission to use, copy, modify, and distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+#
+#---------------------------------------------------------------------------
+
+# serial 1
+
+
+dnl The funny name of this file is intentional in order to make it
+dnl sort alphabetically after any libtool, autoconf or automake
+dnl provided .m4 macro file that might get copied into this same
+dnl subdirectory. This allows that macro (re)definitions from this
+dnl file may override those provided in other files.
+
+
+dnl Override an autoconf provided macro
+dnl -------------------------------------------------
+dnl This macro overrides the one provided by autoconf
+dnl 2.58 or newer, and provides macro definition for
+dnl autoconf 2.57 or older which lack it. This allows
+dnl using libtool 2.2 or newer, which requires that
+dnl this macro is used in configure.ac, with autoconf
+dnl 2.57 or older.
+
+m4_ifdef([AC_CONFIG_MACRO_DIR],
+[dnl
+m4_undefine([AC_CONFIG_MACRO_DIR])dnl
+])
+m4_define([AC_CONFIG_MACRO_DIR],[])
+
+
+dnl XC_OVR_ZZ60
+dnl -------------------------------------------------
+dnl Placing a call to this macro in configure.ac will
+dnl make macros in this file visible to other macros
+dnl used for same configure script, overriding those
+dnl provided elsewhere.
+
+AC_DEFUN([XC_OVR_ZZ60],
+[dnl
+AC_BEFORE([$0],[LT_INIT])dnl
+AC_BEFORE([$0],[AM_INIT_AUTOMAKE])dnl
+AC_BEFORE([$0],[AC_LIBTOOL_WIN32_DLL])dnl
+AC_BEFORE([$0],[AC_PROG_LIBTOOL])dnl
+dnl
+AC_BEFORE([$0],[AC_CONFIG_MACRO_DIR])dnl
+AC_BEFORE([$0],[AC_CONFIG_MACRO_DIRS])dnl
+])
+