In applications using clip planes, set_clip_state is expected to be implemented in the backend. If it is not defined, it may cause the application to segfault.
glClipPlane it is not part of GLES 2, so it is not trivial to reverse engineer if something needs to be done in lima. Other drivers just define a placeholder implementation for set_clip_state, so for now let's just define one for lima too.
This fixes segfault at startup in 'neverball'.