This is because the OpenGL ES group updated the gl2.h header to include a new “const” keyword in this function. Apple updated their headers before we did, which is causing some issues with compatibility. If you go to the OpenGL ES Registry (http://www.khronos.org/registry/gles/) you can download updated headers from there. Simply put these in the “Builds/Include/GLES2” folder in your SDK installation, overwriting the originals. This should allow you to properly build the demos.