Here's a minor update to the patch, that does some extra cleanup:

- don't include longintrepr.h in Objects/abstract.c or 
Objects/boolobject.c --- it's not needed.

- fix several places in longobject.c where int should have been size_t 
or Py_ssize_t

- remove some unnecessary forward declarations in longobject.c.

- fix PyLong_FromLong for small negative integers

At some point I'll try to separate the pure bugfixes (missing casts, int 
vs Py_ssize_t, etc.) from the 15-bit to 30-bit conversion.