merge init-element-branch -> trunk

m4/check-iso-c99.m4

+#
+# We need (at least) two features from the C99 standard: variadic
+# macros and variable length arrays. We check here whether or those
+# are available.
+#
+# Note that we do not further modify the compiler flags, we just check
+# whether variadic macros and variable length arrays are available.
+#
+# The macro takes 2 arguments:
+#
+# $1: optional: a set of compiler flags in addition to CFLAGS
+#
+AC_DEFUN([ALBERTA_ISO_C99_CHECK],
+[AC_REQUIRE([AC_PROG_CC])
+_alberta_save_cflags="${CFLAGS}"
+m4_if($#,1,[CFLAGS="$1"])
+AC_LANG_PUSH([C])
+AC_MSG_CHECKING([for ISO C99 features with "${CC} ${CFLAGS}"])
+AC_COMPILE_IFELSE(
+	[AC_LANG_PROGRAM(
+[[extern void exit(int status);
+#define FOO(a, ...)  (a, __VA_ARGS__)
+extern int foo(int a, int b, int c);]],
+[[int bar[foo FOO(3, 4, 5)];
+exit(bar[0]);]])],
+[AC_MSG_RESULT([variadic macros and variable length arrays available])],
+[AC_MSG_FAILURE([variadic macros and/or vairable length arrays NOT available])])
+AC_LANG_POP([C])
+CFLAGS="${_alberta_save_cflags}"
+])