1.4 Branch & pg_config

Hi

I just noted that the OSX-build of the 1.4 build is broken
due to the inclusion of the pg_dump-in-appbundle patch. The
patch assumes that PG_CONFIG is available inside pkg/mac/Makefile.am,
but the 1.4 buildsystem doesn't know about PG_CONFIG.

Would it be feasable to backport the postgres-specific
changes in the buildsystem to 1.4? If not, please apply
the attached patch. It's the most primitiv patch possible - it adds
AC_SUBST(LIBPQ_HOME) to acinclude.m4, and then hopes
that LIBPQ_HOME/bin/pg_{dump|restore} exists. It's not
pretty, but at least it makes building possible again ;-)

If you plan to backport the buildsystem-changes, then just
ignore this patch ;-)

greetings, Florian Pflug