Merged revisions 151240 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.4

........
  r151240 | kpfleming | 2008-10-20 07:45:56 +0300 (Mon, 20 Oct 2008) | 3 lines
  
  break up acinclude.m4 into individual files, which will make it easier to maintain, easier to add new macros (less patching) and will ease maintenance of these macros across Asterisk branches
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git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@151242 65c4cc65-6c06-0410-ace0-fbb531ad65f3

autoconf/ast_c_define_check.m4

@@ -0,0 +1,33 @@
+# Check if a given macro is defined in a certain header.
+
+# AST_C_DEFINE_CHECK([package], [macro name], [header file], [version])
+AC_DEFUN([AST_C_DEFINE_CHECK],
+[
+    if test "x${PBX_$1}" != "x1"; then
+	AC_MSG_CHECKING([for $2 in $3])
+	saved_cppflags="${CPPFLAGS}"
+	if test "x${$1_DIR}" != "x"; then
+	    $1_INCLUDE="-I${$1_DIR}/include"
+	fi
+	CPPFLAGS="${CPPFLAGS} ${$1_INCLUDE}"
+
+	AC_COMPILE_IFELSE(
+	    [ AC_LANG_PROGRAM( [#include <$3>],
+			       [#if defined($2)
+				int foo = 0;
+			        #else
+			        int foo = bar;
+			        #endif
+				0
+			       ])],
+	    [   AC_MSG_RESULT(yes)
+		PBX_$1=1
+		AC_DEFINE([HAVE_$1], 1, [Define if your system has the $1 headers.])
+		AC_DEFINE([HAVE_$1_VERSION], $4, [Define $1 headers version])
+	    ],
+	    [   AC_MSG_RESULT(no) ] 
+	)
+	CPPFLAGS="${saved_cppflags}"
+    fi
+    AC_SUBST(PBX_$1)
+])