From 09b7b4719d2d3211e14203606d824e768611ff73 Mon Sep 17 00:00:00 2001
From: Rob McDonald <rob.a.mcdonald@gmail.com>
Date: Wed, 15 Mar 2023 10:45:53 -0700
Subject: [PATCH] Protect GL_SILENCE_DEPRECATION from re-definition.

---
 FL/gl.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/FL/gl.h b/FL/gl.h
index e47c66e3c..7b5e9c4d7 100644
--- a/FL/gl.h
+++ b/FL/gl.h
@@ -55,7 +55,9 @@
 #  endif
 
 #  ifdef __APPLE__ // PORTME: OpenGL path abstraction
-#  define GL_SILENCE_DEPRECATION 1
+#    ifndef GL_SILENCE_DEPRECATION
+#      define GL_SILENCE_DEPRECATION 1
+#    endif
 #    if !defined(__gl3_h_) // make sure OpenGL/gl3.h was not included before
 #      include <OpenGL/gl.h>
 #    endif