From e7a81f8aaab94424ac2650c779cb13aec648e7e4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Camilla=20L=C3=B6wy?= <elmindreda@elmindreda.org>
Date: Tue, 15 Mar 2022 17:51:57 +0100
Subject: [PATCH] Fix GLAPIENTRY redefinition warning

On a Unix system, if you define GLFW_INCLUDE_NONE and
GLFW_EXPOSE_NATIVE_GLX, then include glfw3.h and glfw3native.h, you will
get a redefinition warning for GLAPIENTRY.

The glfw3.h header defines GLAPIENTRY as a service for OpenGL related
headers that assume it's already defined.  However, glx.h includes gl.h,
which defines GLAPIENTRY unconditionally.

If not for Hyrum's law, the better solution would have been not to
define GLAPIENTRY if GLFW_INCLUDE_NONE is defined.

Fixes #2010

This is adapted to 3.3-stable from
535c3ce63240ee91f998219b35dc82abef545c3d and
ce85c7dcaf48be96870f2d8fec1d78b0b7d744c7.
---
 include/GLFW/glfw3.h       |  1 +
 include/GLFW/glfw3native.h | 16 ++++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/include/GLFW/glfw3.h b/include/GLFW/glfw3.h
index cd019a79..f7ab3828 100644
--- a/include/GLFW/glfw3.h
+++ b/include/GLFW/glfw3.h
@@ -5900,6 +5900,7 @@ GLFWAPI VkResult glfwCreateWindowSurface(VkInstance instance, GLFWwindow* window
  */
 #ifndef GLAPIENTRY
  #define GLAPIENTRY APIENTRY
+ #define GLFW_GLAPIENTRY_DEFINED
 #endif
 
 /* -------------------- END SYSTEM/COMPILER SPECIFIC --------------------- */
diff --git a/include/GLFW/glfw3native.h b/include/GLFW/glfw3native.h
index fe74c733..212a458b 100644
--- a/include/GLFW/glfw3native.h
+++ b/include/GLFW/glfw3native.h
@@ -111,12 +111,28 @@ extern "C" {
  /* NSGL is declared by Cocoa.h */
 #endif
 #if defined(GLFW_EXPOSE_NATIVE_GLX)
+ /* This is a workaround for the fact that glfw3.h defines GLAPIENTRY because by
+  * default it also acts as an OpenGL header
+  * However, glx.h will include gl.h, which will define it unconditionally
+  */
+ #if defined(GLFW_GLAPIENTRY_DEFINED)
+  #undef GLAPIENTRY
+  #undef GLFW_GLAPIENTRY_DEFINED
+ #endif
  #include <GL/glx.h>
 #endif
 #if defined(GLFW_EXPOSE_NATIVE_EGL)
  #include <EGL/egl.h>
 #endif
 #if defined(GLFW_EXPOSE_NATIVE_OSMESA)
+ /* This is a workaround for the fact that glfw3.h defines GLAPIENTRY because by
+  * default it also acts as an OpenGL header
+  * However, osmesa.h will include gl.h, which will define it unconditionally
+  */
+ #if defined(GLFW_GLAPIENTRY_DEFINED)
+  #undef GLAPIENTRY
+  #undef GLFW_GLAPIENTRY_DEFINED
+ #endif
  #include <GL/osmesa.h>
 #endif