Added includes for OpenGL ES1 and ES2.

include/osg/GL

@@ -14,16 +14,9 @@
 #ifndef OSG_GL
 #define OSG_GL 1
 
-#ifndef WIN32
+#include <osg/Config>
 
-    // Non Windows, doesn't require nonsense as seen below :-)    
-    #ifndef __gl_h_
-        #ifdef __APPLE__
-            #include <OpenGL/gl.h>
-        #else
-            #include <GL/gl.h>
-        #endif
-    #endif
+#ifndef WIN32
 
     // Required for compatibility with glext.h sytle function definitions of 
     // OpenGL extensions, such as in src/osg/Point.cpp.
@@ -84,16 +77,34 @@
         #define _WCHAR_T_DEFINED
     #endif
 
-    #ifndef __gl_h_
-        #include <GL/gl.h>
-    #endif
-
 #endif // WIN32
 
+#if defined(OSG_GLES1_AVAILABLE)
+
+    #include <GLES/gl.h>
+
+#elif defined(OSG_GLES2_AVAILABLE)
+
+    #include <GLES2/gl2.h>
+
+#else
+
+    #ifndef __gl_h_
+        #ifdef __APPLE__
+            #include <OpenGL/gl.h>
+        #else
+            #include <GL/gl.h>
+        #endif
+    #endif
+
+#endif
+
+
+#ifdef OSG_GL_MATRICES_AVAILABLE
     inline void glLoadMatrix(const float* mat) { glLoadMatrixf(static_cast<const GLfloat*>(mat)); }
     inline void glLoadMatrix(const double* mat) { glLoadMatrixd(static_cast<const GLdouble*>(mat)); }
     inline void glMultMatrix(const float* mat) { glMultMatrixf(static_cast<const GLfloat*>(mat)); }
     inline void glMultMatrix(const double* mat) { glMultMatrixd(static_cast<const GLdouble*>(mat)); }
-    
+#endif
 
 #endif  // __osgGL_h