title: What is "OpenGLES/ES2/gl.h file is not found" in xcode?
body: <p>My application is working on simulator.There is no any error.But when running on iPhone device I get to this error </p>
  
  <p>OpenGLES/ES2/gl.h  is not found  </p>
  
  <p>Error location 
  iphoneOS6.1->Frameworks->CoreVideo.framework->CVOpenGLESTexture.h</p>
  
  <p>I did not use this framework in my application.What is CVOpenGLESTexture.h ?Why I get to this error when running on device ?</p>