pgsql: Make snprintf() use already-defined int64/uint64 typedefs rather

Log Message:
-----------
Make snprintf() use already-defined int64/uint64 typedefs rather than
defining its own.

Modified Files:
--------------
pgsql/src/port:
snprintf.c (r1.8 -> r1.9)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/port/snprintf.c.diff?r1=1.8&r2=1.9)