configure: Force #undef of 'near' and 'far' on Windows

This adds an extra header that gets included from config.h where we
can add configuration defines. This is used to #undef 'near' and 'far'
when building for Windows so that we don't have to avoid using them as
variable names in the Cogl code.

Makefile.am

@@ -8,4 +8,6 @@ SUBDIRS += examples doc po
 
 ACLOCAL_AMFLAGS = -I build/autotools ${ACLOCAL_FLAGS}
 
-EXTRA_DIST = README.in
+EXTRA_DIST = \
+	README.in \
+	config-custom.h

config-custom.h

@@ -0,0 +1,35 @@
+/*
+ * Cogl
+ *
+ * An object oriented GL/GLES Abstraction/Utility Layer
+ *
+ * Copyright (C) 2011 Intel Corporation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* The contents of this file get #included by config.h so it is
+   intended for extra configuration that needs to be included by all
+   Cogl source files. */
+
+/* The windows headers #define 'near' and 'far' to be blank. We
+   commonly want to use these variable names for doing perspective
+   transformation so rather than having to workaround this mis-feature
+   in Windows in the code we just #undef them here. We need to do this
+   after including windows.h */
+#ifdef _WIN32
+#include <windows.h>
+#undef near
+#undef far
+#endif /* _WIN32 */

configure.ac

@@ -100,6 +100,7 @@ AM_INIT_AUTOMAKE([1.11 foreign -Wno-portability no-define no-dist-gzip
                   dist-bzip2])
 AM_SILENT_RULES([yes])
 
+AH_BOTTOM([#include "config-custom.h"])
 
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