Added android version too

src/Environment.cpp

@@ -1,8 +1,13 @@
 #include "Environment.h"
 
 #include "utils/Utils.h"
-#include <GL/gl.h>
 
+#ifdef __ANDROID__
+#include <GLES2/gl2.h>
+#include <GLES2/gl2ext.h>
+#else
+#include <GL/gl.h>
+#endif
 namespace ZL {
 
 int Environment::windowHeaderHeight = 0;