1 files changed, 133 insertions, 0 deletions
diff --git a/m4/fr_smart_check_include.m4 b/m4/fr_smart_check_include.m4
new file mode 100644
index 0000000..e7d4443
--- /dev/null
+++ b/m4/fr_smart_check_include.m4
@@ -0,0 +1,133 @@
+dnl #
+dnl #  Look for a header file in a number of places.
+dnl #
+dnl #  FR_SMART_CHECK_INCLUDE(foo.h, [ #include <other.h> ])
+dnl #
+AC_DEFUN([FR_SMART_CHECK_INCLUDE], [
+
+ac_safe=`echo "$1" | sed 'y%./+-%__pm%'`
+old_CPPFLAGS="$CPPFLAGS"
+smart_include=
+dnl #  The default directories we search in (in addition to the compilers search path)
+smart_include_dir="/usr/local/include /opt/include"
+
+dnl #  Our local versions
+_smart_try_dir=
+_smart_include_dir=
+
+dnl #  Add variants with the different prefixes and one with no prefix
+for _prefix in $smart_prefix ""; do
+  for _dir in $smart_try_dir; do
+    _smart_try_dir="${_smart_try_dir} ${_dir}/${_prefix}"
+  done
+
+  for _dir in $smart_include_dir; do
+    _smart_include_dir="${_smart_include_dir} ${_dir}/${_prefix}"
+  done
+done
+
+dnl #
+dnl #  Try any user-specified directory first otherwise we may pick up
+dnl #  the wrong version.
+dnl #
+if test "x$_smart_try_dir" != "x"; then
+  for try in $_smart_try_dir; do
+    AC_MSG_CHECKING([for $1 in $try])
+    CPPFLAGS="-isystem $try $old_CPPFLAGS"
+    AC_TRY_COMPILE([$2
+		    #include <$1>],
+		   [int a = 1;],
+		   [
+		     smart_include="-isystem $try"
+		     AC_MSG_RESULT(yes)
+		     break
+		   ],
+		   [
+		     smart_include=
+		     AC_MSG_RESULT(no)
+		   ])
+  done
+  CPPFLAGS="$old_CPPFLAGS"
+fi
+
+dnl #
+dnl #  Try using the default includes (with prefixes).
+dnl #
+if test "x$smart_include" = "x"; then
+  for _prefix in $smart_prefix; do
+    AC_MSG_CHECKING([for ${_prefix}/$1])
+
+    AC_TRY_COMPILE([$2
+		    #include <$1>],
+		   [int a = 1;],
+		   [
+		     smart_include="-isystem ${_prefix}/"
+		     AC_MSG_RESULT(yes)
+		     break
+		   ],
+		   [
+		     smart_include=
+		     AC_MSG_RESULT(no)
+		   ])
+  done
+fi
+
+dnl #
+dnl #  Try using the default includes (without prefixes).
+dnl #
+if test "x$smart_include" = "x"; then
+    AC_MSG_CHECKING([for $1])
+
+    AC_TRY_COMPILE([$2
+		    #include <$1>],
+		   [int a = 1;],
+		   [
+		     smart_include=" "
+		     AC_MSG_RESULT(yes)
+		     break
+		   ],
+		   [
+		     smart_include=
+		     AC_MSG_RESULT(no)
+		   ])
+fi
+
+dnl #
+dnl #  Try to guess possible locations.
+dnl #
+if test "x$smart_include" = "x"; then
+
+  for try in $_smart_include_dir; do
+    AC_MSG_CHECKING([for $1 in $try])
+    CPPFLAGS="-isystem $try $old_CPPFLAGS"
+    AC_TRY_COMPILE([$2
+		    #include <$1>],
+		   [int a = 1;],
+		   [
+		     smart_include="-isystem $try"
+		     AC_MSG_RESULT(yes)
+		     break
+		   ],
+		   [
+		     smart_include=
+		     AC_MSG_RESULT(no)
+		   ])
+  done
+  CPPFLAGS="$old_CPPFLAGS"
+fi
+
+dnl #
+dnl #  Found it, set the appropriate variable.
+dnl #
+if test "x$smart_include" != "x"; then
+  eval "ac_cv_header_$ac_safe=yes"
+  CPPFLAGS="$smart_include $old_CPPFLAGS"
+  SMART_CPPFLAGS="$smart_include $SMART_CPPFLAGS"
+fi
+
+dnl #
+dnl #  Consume prefix, it's not likely to be used
+dnl #  between multiple calls.
+dnl #
+smart_prefix=
+])