Adding upstream version 16.2.upstream/16.2

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

1 files changed, 116 insertions, 0 deletions

diff --git a/config/check_decls.m4 b/config/check_decls.m4
new file mode 100644
index 0000000..f1b90c5
--- /dev/null
+++ b/config/check_decls.m4
@@ -0,0 +1,116 @@
+# config/check_decls.m4
+
+# This file redefines the standard Autoconf macro _AC_CHECK_DECL_BODY,
+# and adds a supporting function _AC_UNDECLARED_WARNING, to make
+# AC_CHECK_DECLS behave correctly when checking for built-in library
+# functions with clang.
+
+# This is based on commit 82ef7805faffa151e724aa76c245ec590d174580
+# in the Autoconf git repository.  We can drop it if they ever get
+# around to releasing a new version of Autoconf.  In the meantime,
+# it's distributed under Autoconf's license:
+
+# This file is part of Autoconf.  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.
+#
+# Under Section 7 of GPL version 3, you are granted additional
+# permissions described in the Autoconf Configure Script Exception,
+# version 3.0, as published by the Free Software Foundation.
+#
+# You should have received a copy of the GNU General Public License
+# and a copy of the Autoconf Configure Script Exception along with
+# this program; see the files COPYINGv3 and COPYING.EXCEPTION
+# respectively.  If not, see <http://www.gnu.org/licenses/>.
+
+# Written by David MacKenzie, with help from
+# Franc,ois Pinard, Karl Berry, Richard Pixley, Ian Lance Taylor,
+# Roland McGrath, Noah Friedman, david d zuhn, and many others.
+
+
+# _AC_UNDECLARED_WARNING
+# ----------------------
+# Set ac_[]_AC_LANG_ABBREV[]_decl_warn_flag=yes if the compiler uses a warning,
+# not a more-customary error, to report some undeclared identifiers.  Fail when
+# an affected compiler warns also on valid input.  _AC_PROG_PREPROC_WORKS_IFELSE
+# solves a related problem.
+AC_DEFUN([_AC_UNDECLARED_WARNING],
+[# The Clang compiler raises a warning for an undeclared identifier that matches
+# a compiler builtin function.  All extant Clang versions are affected, as of
+# Clang 3.6.0.  Test a builtin known to every version.  This problem affects the
+# C and Objective C languages, but Clang does report an error under C++ and
+# Objective C++.
+#
+# Passing -fno-builtin to the compiler would suppress this problem.  That
+# strategy would have the advantage of being insensitive to stray warnings, but
+# it would make tests less realistic.
+AC_CACHE_CHECK([how $[]_AC_CC[] reports undeclared, standard C functions],
+[ac_cv_[]_AC_LANG_ABBREV[]_decl_report],
+[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [(void) strchr;])],
+  [AS_IF([test -s conftest.err], [dnl
+    # For AC_CHECK_DECL to react to warnings, the compiler must be silent on
+    # valid AC_CHECK_DECL input.  No library function is consistently available
+    # on freestanding implementations, so test against a dummy declaration.
+    # Include always-available headers on the off chance that they somehow
+    # elicit warnings.
+    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([dnl
+#include <float.h>
+#include <limits.h>
+#include <stdarg.h>
+#include <stddef.h>
+extern void ac_decl (int, char *);],
+[@%:@ifdef __cplusplus
+  (void) ac_decl ((int) 0, (char *) 0);
+  (void) ac_decl;
+@%:@else
+  (void) ac_decl;
+@%:@endif
+])],
+      [AS_IF([test -s conftest.err],
+	[AC_MSG_FAILURE([cannot detect from compiler exit status or warnings])],
+	[ac_cv_[]_AC_LANG_ABBREV[]_decl_report=warning])],
+      [AC_MSG_FAILURE([cannot compile a simple declaration test])])],
+    [AC_MSG_FAILURE([compiler does not report undeclared identifiers])])],
+  [ac_cv_[]_AC_LANG_ABBREV[]_decl_report=error])])
+
+case $ac_cv_[]_AC_LANG_ABBREV[]_decl_report in
+  warning) ac_[]_AC_LANG_ABBREV[]_decl_warn_flag=yes ;;
+  *) ac_[]_AC_LANG_ABBREV[]_decl_warn_flag= ;;
+esac
+])# _AC_UNDECLARED_WARNING
+
+# _AC_CHECK_DECL_BODY
+# -------------------
+# Shell function body for AC_CHECK_DECL.
+m4_define([_AC_CHECK_DECL_BODY],
+[  AS_LINENO_PUSH([$[]1])
+  # Initialize each $ac_[]_AC_LANG_ABBREV[]_decl_warn_flag once.
+  AC_DEFUN([_AC_UNDECLARED_WARNING_]_AC_LANG_ABBREV,
+	   [_AC_UNDECLARED_WARNING])dnl
+  AC_REQUIRE([_AC_UNDECLARED_WARNING_]_AC_LANG_ABBREV)dnl
+  [as_decl_name=`echo $][2|sed 's/ *(.*//'`]
+  [as_decl_use=`echo $][2|sed -e 's/(/((/' -e 's/)/) 0&/' -e 's/,/) 0& (/g'`]
+  AC_CACHE_CHECK([whether $as_decl_name is declared], [$[]3],
+  [ac_save_werror_flag=$ac_[]_AC_LANG_ABBREV[]_werror_flag
+  ac_[]_AC_LANG_ABBREV[]_werror_flag="$ac_[]_AC_LANG_ABBREV[]_decl_warn_flag$ac_[]_AC_LANG_ABBREV[]_werror_flag"
+  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([$[]4],
+[@%:@ifndef $[]as_decl_name
+@%:@ifdef __cplusplus
+  (void) $[]as_decl_use;
+@%:@else
+  (void) $[]as_decl_name;
+@%:@endif
+@%:@endif
+])],
+		   [AS_VAR_SET([$[]3], [yes])],
+		   [AS_VAR_SET([$[]3], [no])])
+  ac_[]_AC_LANG_ABBREV[]_werror_flag=$ac_save_werror_flag])
+  AS_LINENO_POP
+])# _AC_CHECK_DECL_BODY