Enable SDL to compile on macOS

.github/workflows/build.yml

@@ -177,6 +177,20 @@ jobs:
         run: |
           ./bin/OSX/AutomatedTest null
 
+  macos-sdl:
+    runs-on: macos-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Install deps
+        run: |
+          brew update
+          brew install cmake libpng jpeg sdl2
+
+      - name: Build
+        run: |
+          cmake . -DCMAKE_FIND_FRAMEWORK=LAST -DBUILD_EXAMPLES=1 -DUSE_SDL2=1
+          make -j3
+
   msvc:
     name: VS 2019 ${{ matrix.config.arch }} ${{ matrix.sdl.label }}
     runs-on: windows-2019

source/Irrlicht/COpenGLCommon.h

@@ -23,7 +23,7 @@
 	#endif
 	#include <OpenGL/gl.h>
 	#if defined(_IRR_OPENGL_USE_EXTPOINTER_)
-		#include <GL/glext.h>
+		#error glext.h missing on OSX
 	#endif
 #elif defined(_IRR_COMPILE_WITH_SDL_DEVICE_) && !defined(_IRR_COMPILE_WITH_X11_DEVICE_)
 	#if defined(_IRR_OPENGL_USE_EXTPOINTER_)
@@ -34,9 +34,12 @@
 	#include <SDL_video.h>
 	#include <SDL_opengl.h>
 	#if defined(_IRR_OPENGL_USE_EXTPOINTER_)
-		// The SDL2 header doesn't cut it for extensions
+		#ifdef __APPLE__
+		#include <SDL_opengl_glext.h>
+		#else
 		#include <GL/glext.h>
 		#endif
+	#endif
 #else
 	#if defined(_IRR_OPENGL_USE_EXTPOINTER_)
 		#define GL_GLEXT_LEGACY 1