Try this on Android: http://developer.android.com/reference/android/opengl/GLU.html#gluErrorString(int) and this on iOS: https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man3/gluErrorString.3.html
If those don't work for you, you can always create your own mapping from the integer error value to a corresponding string - it should be easy since there's only a handful of error values. Just look up the error values from the gl2.h
and gl.h
headers (they start with 0x05).