SDL: Added SDL_USE_BUILTIN_OPENGL_DEFINITIONS to avoid system OpenGL headers

SDL Commits
1 
From 8f58bb9cf85e1e801e8140f883275cd943b031e3 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Thu, 21 Oct 2021 20:48:08 -0700
Subject: [PATCH] Added SDL_USE_BUILTIN_OPENGL_DEFINITIONS to avoid system
 OpenGL headers

---
 include/SDL_egl.h       | 3 +--
 include/SDL_opengles2.h | 2 +-
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/include/SDL_egl.h b/include/SDL_egl.h
index 62bc0b4283..d00b26f8fc 100644
--- a/include/SDL_egl.h
+++ b/include/SDL_egl.h
@@ -24,7 +24,7 @@
  *
  *  This is a simple file to encapsulate the EGL API headers.
  */
-#if !defined(_MSC_VER) && !defined(__ANDROID__)
+#if !defined(_MSC_VER) && !defined(__ANDROID__) && !defined(SDL_USE_BUILTIN_OPENGL_DEFINITIONS)
 
 #if defined(__vita__) || defined(__psp2__)
 #include <psp2/types.h>
@@ -1676,5 +1676,4 @@ EGLAPI EGLuint64NV EGLAPIENTRY eglGetSystemTimeNV (void);
 
 #endif /* __eglext_h_ */
 
-
 #endif /* _MSC_VER */
diff --git a/include/SDL_opengles2.h b/include/SDL_opengles2.h
index ce114ae1b1..876e965112 100644
--- a/include/SDL_opengles2.h
+++ b/include/SDL_opengles2.h
@@ -26,7 +26,7 @@
  */
 #include "SDL_config.h"
 
-#ifndef _MSC_VER
+#if !defined(_MSC_VER) && !defined(SDL_USE_BUILTIN_OPENGL_DEFINITIONS)
 
 #ifdef __IPHONEOS__
 #include <OpenGLES/ES2/gl.h>