cogl: Make cogl-config.h include check explicit

Don't rely on some combination of macros, but an explicit definition to
check whether cogl-config.h was included.

cogl/cogl-mutter-config.h.in

@@ -3,3 +3,5 @@
 
 /* Have GLES 2.0 for rendering */
 #undef HAVE_COGL_GLES2
+
+#define COGL_CONFIG_H_INCLUDED 1

cogl/cogl/cogl-util.h

@@ -40,9 +40,7 @@
 #include <stdio.h>
 
 /* Double check that config.h has been included */
-#if (!defined (PACKAGE_NAME) && \
-     !defined (_COGL_IN_TEST_BITMASK) && \
-     !defined(COGL_ENABLE_MUTTER_API))
+#ifndef COGL_CONFIG_H_INCLUDED
 #error "cogl-config.h must be included before including cogl-util.h"
 #endif
 

cogl/configure.ac

@@ -673,6 +673,8 @@ AC_SUBST(COGL_EXTRA_LDFLAGS)
 MAINTAINER_CFLAGS=
 AC_SUBST(MAINTAINER_CFLAGS)
 
+AC_DEFINE([COGL_CONFIG_H_INCLUDED], 1, [cogl-config.h was included])
+
 AC_OUTPUT(
 Makefile
 test-fixtures/Makefile