Log Message:
-----------
Make saveHistory work properly on OS X when HISTFILE is set to /dev/null.
Per discussion with Martin Atukunda.
Modified Files:
--------------
pgsql/src/bin/psql:
input.c (r1.57 -> r1.58)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/input.c.diff?r1=1.57&r2=1.58)