I have a Problem when I try to compiling my iOS project with iOS 8.
The errors messages are:
Implicit declaration of function 'glReadPixels' is invalid in C99 compiling
Conflicting types for 'glReadPixels'
Declaration of 'glReadPixels' must be imported from module 'OpenGLES.ES3.gl' before it is required
Recently I have faced the same issue.
The easiest way to resolve this problem is by adding
@import OpenGLES; line in each file where you have got this message.