Remove glewexperimental flag

src/graphics/glwrap.cpp

@@ -105,10 +105,6 @@ void initGL()
     if (is_gl_init)
         return;
     is_gl_init = true;
-    // For Mesa extension reporting
-#ifdef  __linux__ 
-    glewExperimental = GL_TRUE;
-#endif
     GLenum err = glewInit();
     if (GLEW_OK != err)
         Log::fatal("GLEW", "Glew initialisation failed with error %s", glewGetErrorString(err));
@@ -762,4 +758,4 @@ const std::string getGLExtensions()
     }
 
     return result;
-}   // getGLExtensions
+}   // getGLExtensions