From 4d46f276f847a39db182fe55a2fbb244f4fc6b34 Mon Sep 17 00:00:00 2001
From: Andreas Rönnquist <andreas@ronnquist.net>
Date: Wed, 12 Dec 2018 16:27:37 +0100
Subject: Fix building with Mesa 18.2.5 and later

Based on the patch on Allegro5,
https://github.com/liballeg/allegro5/commit/a40d30e21802ecf5c9382cf34af9b01bd3781e47

diff --git a/addons/allegrogl/include/alleggl.h b/addons/allegrogl/include/alleggl.h
index 12d71c3c5a62..fa36c9844ac2 100644
--- a/addons/allegrogl/include/alleggl.h
+++ b/addons/allegrogl/include/alleggl.h
@@ -62,10 +62,14 @@ typedef __int64 INT64;
 
 /* HACK: Prevent both Mesa and SGI's broken headers from screwing us */
 #define __glext_h_
+#define __gl_glext_h_
 #define __glxext_h_
+#define __glx_glxext_h_
 #include <GL/gl.h>
 #undef  __glext_h_
+#undef  __gl_glext_h_
 #undef  __glxext_h_
+#undef  __glx_glxext_h_
 
 #endif /* ALLEGRO_MACOSX */
 
diff --git a/addons/allegrogl/include/allegrogl/GLext/glx_ext_defs.h b/addons/allegrogl/include/allegrogl/GLext/glx_ext_defs.h
index 6b2e5712053a..30f0dce236d0 100644
--- a/addons/allegrogl/include/allegrogl/GLext/glx_ext_defs.h
+++ b/addons/allegrogl/include/allegrogl/GLext/glx_ext_defs.h
@@ -1,6 +1,8 @@
 /* HACK: Prevent both Mesa and SGI's broken headers from screwing us */
 #define __glxext_h_
+#define __glx_glxext_h_
 #include <GL/glx.h>
+#undef __glx_glxext_h_
 #undef __glxext_h_
 
 #ifndef GLX_VERSION_1_3