python - pq: Include stdint dot h.

Log Message:
-----------
Include stdint dot h.

FreeBSD and Windows(mingw32) didn't require it. However, other systems, like
Darwin, seem to want it.

Modified Files:
--------------
pq/src:
buffer.c (r1.2 -> r1.3)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/python/pq/src/buffer.c.diff?r1=1.2&r2=1.3)