Fixed macOS compilation by bypassing GL library check

SConstruct

@@ -1397,6 +1397,9 @@ static void terminate_handler()
 		if self.user_settings.opengles:
 			# GLES builds do not use the GL utility functions
 			return
+		if sys.platform == 'darwin':
+			# macOS provides these in a system framework, so this test always fails
+			return
 		self._check_system_library(context, header=['GL/glu.h'], main='''
 	gluPerspective(90.0,1.0,0.1,5000.0);
 	gluBuild2DMipmaps (GL_TEXTURE_2D, 0, 1, 1, 1, GL_UNSIGNED_BYTE, nullptr);