[gnome-builder] build: ensure C11 is supported by C compiler

[Christian Hergert <chergert src gnome org>]

commit aec315e0c62724bd0bf82b93f408bb4784733912
Author: Christian Hergert <christian hergert me>
Date:   Thu May 7 20:38:36 2015 -0700

    build: ensure C11 is supported by C compiler

 configure.ac |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 755f44f..6370689 100644
--- a/configure.ac
+++ b/configure.ac
@@ -68,6 +68,15 @@ AC_PATH_PROG([GLIB_COMPILE_RESOURCES], [glib-compile-resources])
 AC_HEADER_STDC
 PKG_PROG_PKG_CONFIG([0.22])
 
+
+dnl ***********************************************************************
+dnl Ensure C11 is Supported
+dnl ***********************************************************************
+AX_CHECK_COMPILE_FLAG([-std=c11],
+                      [CFLAGS="$CFLAGS -std=c11"],
+                      [AC_MSG_ERROR([C compiler cannot compile C11 code])])
+
+
 dnl ***********************************************************************
 dnl Find Path of GNU Make
 dnl ***********************************************************************