GRAPHICS: Move common OpenGL files into graphics/opengl

graphics/opengl/system_headers.h

@@ -0,0 +1,52 @@
+/* ResidualVM - A 3D game interpreter
+ *
+ * ResidualVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+
+#ifndef GRAPHICS_SYSTEM_HEADERS_H
+#define GRAPHICS_SYSTEM_HEADERS_H
+
+#include "common/scummsys.h"
+
+#ifdef USE_GLES2
+
+#define GL_GLEXT_PROTOTYPES
+#ifdef IPHONE
+#include <OpenGLES/ES2/gl.h>
+#include <OpenGLES/ES2/glext.h>
+#else
+#include <GLES2/gl2.h>
+#include <GLES2/gl2ext.h>
+#endif
+#undef GL_GLEXT_PROTOTYPES
+
+#ifndef GL_BGRA
+#	define GL_BGRA GL_BGRA_EXT
+#endif
+
+#elif defined(USE_GLEW)
+#include <GL/glew.h>
+#elif defined(SDL_BACKEND) && defined(USE_OPENGL)
+#include <SDL_opengl.h>
+#elif defined(USE_OPENGL)
+#include <GL/gl.h>
+#endif
+
+#endif