During one of the Metal WWDC presentations, they mentioned that OpenGL shaders will automatically get translated to Metal, no work needs to be done on the developer's end.
There's a known bug in iOS 9.x SpriteKit where any shader that uses gl_FragCoord (very common) crashes with a Metal error on Metal compatible devices (it works fine in the simulator or devices that do not support Metal).
My question is: Is there any way to stop this auto translation of OpenGL shaders to Metal? A compiler flag or anything to tell the program to never use Metal or translate anything to Metal?