The change in PyCode_HasFreeVars and PyFrame_SetLineNumber will also
effect Cython under PyPy. So add those two functions for PyPy. But
didn't test those yet.

[ @kirr: we might want to restructure pycapicompat.h in the future to be
  driven by function name as primary key. Not sure for now though - we'll
  see how it goes ]

/reviewed-by @kirr
/reviewed-on !2