$OpenBSD: patch-include_SDL_opengl_h,v 1.3 2019/01/28 06:47:56 jsg Exp $
Index: include/SDL_opengl.h
--- include/SDL_opengl.h.orig
+++ include/SDL_opengl.h
@@ -35,7 +35,12 @@
 #endif
 #ifndef NO_SDL_GLEXT
 #define __glext_h_  /* Don't let gl.h include glext.h */
+#define __gl_glext_h_  /* Don't let gl.h include glext.h */
+#ifndef GL_ARB_shader_objects
+#define GL_ARB_shader_objects 0
+#define undef_GL_ARB
 #endif
+#endif
 #if defined(__MACOSX__)
 #include <OpenGL/gl.h>	/* Header File For The OpenGL Library */
 #include <OpenGL/glu.h>	/* Header File For The GLU Library */
@@ -48,6 +53,11 @@
 #endif
 #ifndef NO_SDL_GLEXT
 #undef __glext_h_
+#undef __gl_glext_h_
+#ifdef undef_GL_ARB
+#undef GL_ARB_shader_objects
+#undef undef_GL_ARB
+#endif
 #endif
 
 /** @name GLext.h
