Added basic Window interface

3rdparty/include/SDL/SDL_opengles.h

@@ -0,0 +1,39 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2020 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+/**
+ *  \file SDL_opengles.h
+ *
+ *  This is a simple file to encapsulate the OpenGL ES 1.X API headers.
+ */
+#include "SDL_config.h"
+
+#ifdef __IPHONEOS__
+#include <OpenGLES/ES1/gl.h>
+#include <OpenGLES/ES1/glext.h>
+#else
+#include <GLES/gl.h>
+#include <GLES/glext.h>
+#endif
+
+#ifndef APIENTRY
+#define APIENTRY
+#endif