Ported osgUtil, osgDB, osgGA, NodeKits and plugins to compile against OpenGL ES 1.1 and OpenGL ES 2.0.

src/osgViewer/ScreenCaptureHandler.cpp

@@ -490,7 +490,9 @@ void WindowCaptureCallback::setCaptureOperation(ScreenCaptureHandler::CaptureOpe
 
 void WindowCaptureCallback::operator () (osg::RenderInfo& renderInfo) const
 {
+#if !defined(OSG_GLES1_AVAILABLE) && !defined(OSG_GLES2_AVAILABLE)
     glReadBuffer(_readBuffer);
+#endif
 
     osg::GraphicsContext* gc = renderInfo.getState()->getGraphicsContext();
     osg::ref_ptr<ContextData> cd = getContextData(gc);