[mutter] cogl: Make _Static_assert non-optional

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 9846a4d812cc8771faa67c16bd511b7652d64aed
Author: Jonas Ådahl <jadahl gmail com>
Date:   Thu May 3 20:16:35 2018 +0200

    cogl: Make _Static_assert non-optional

 cogl/cogl-mutter-config.h.in | 3 ---
 cogl/cogl/cogl-util.h        | 7 -------
 cogl/configure.ac            | 6 ++----
 3 files changed, 2 insertions(+), 14 deletions(-)
---
diff --git a/cogl/cogl-mutter-config.h.in b/cogl/cogl-mutter-config.h.in
index bc7f146ce..83e3a9eda 100644
--- a/cogl/cogl-mutter-config.h.in
+++ b/cogl/cogl-mutter-config.h.in
@@ -12,6 +12,3 @@
 
 /* Define to 1 if you have the `memmem' function. */
 #undef HAVE_MEMMEM
-
-/* Whether _Static_assert can be used or not */
-#undef HAVE_STATIC_ASSERT
diff --git a/cogl/cogl/cogl-util.h b/cogl/cogl/cogl-util.h
index 376d177bc..a821e55c4 100644
--- a/cogl/cogl/cogl-util.h
+++ b/cogl/cogl/cogl-util.h
@@ -218,16 +218,9 @@ _cogl_util_pixel_format_from_masks (unsigned long r_mask,
  * Allows you to assert that an expression evaluates to true at
  * compile time and aborts compilation if not. If possible message
  * will also be printed if the assertion fails.
- *
- * Note: Only Gcc >= 4.6 supports the c11 _Static_assert which lets us
- * print a nice message if the compile time assertion fails.
  */
-#ifdef HAVE_STATIC_ASSERT
 #define _COGL_STATIC_ASSERT(EXPRESSION, MESSAGE) \
   _Static_assert (EXPRESSION, MESSAGE);
-#else
-#define _COGL_STATIC_ASSERT(EXPRESSION, MESSAGE)
-#endif
 
 #ifdef HAVE_MEMMEM
 #define _cogl_util_memmem memmem
diff --git a/cogl/configure.ac b/cogl/configure.ac
index 3be282fc2..7566d7fc9 100644
--- a/cogl/configure.ac
+++ b/cogl/configure.ac
@@ -173,10 +173,8 @@ dnl     ============================================================
 AC_MSG_CHECKING([for _Static_assert])
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([_Static_assert (1, "");],
                                    [(void) 0])],
-                  [AC_DEFINE([HAVE_STATIC_ASSERT], [1],
-                             [Whether _Static_assert can be used or not])
-                   AC_MSG_RESULT([yes])],
-                  [AC_MSG_RESULT([no])])
+                  [AC_MSG_RESULT([yes])],
+                  [AC_MSG_ERROR([Missing _Static_assert])])
 
 dnl ================================================================
 dnl Libtool stuff.