Apply workaround patch for compiling against nvidia headers posted as

#2819332 by larryhaja. It reports that the patch fixes compilation for him
and it doesn't break it for me so hopefully there aren't regressions.
Said that i've tried to define GL_GLEXT_PROTOTYPES at configure time but
it breaks compilation and making OGLRender.cpp:133 not optional looks way
more risky.

desmume/src/OGLRender.cpp

@@ -54,6 +54,10 @@ static void ENDGL() {
 #else
 	#include <GL/gl.h>
 	#include <GL/glext.h>
+	/* This is a workaround needed to compile against nvidia GL headers */
+	#ifndef GL_ALPHA_BLEND_EQUATION_ATI
+	#undef GL_VERSION_1_3
+	#endif
 #endif
 #endif