-# force this include dir no matter what, so we get sane headers.
-include_directories("${DEPDIR}/OpenGL")
+# force this include dir no matter what on Windows, so we get sane headers.
+if(NOT WIN32)
+ option (LUGARU_FORCE_INTERNAL_OPENGL "Force internal OpenGL headers, even if there's a system version" True)
+ if (LUGARU_FORCE_INTERNAL_OPENGL)
+ include_directories("${DEPDIR}/OpenGL")
+ endif (LUGARU_FORCE_INTERNAL_OPENGL)
+endif(NOT WIN32)
+
+if(WIN32)
+ include_directories("${DEPDIR}/OpenGL")
+endif(WIN32)