MacOS X and external functions - Mailing list pgsql-general

I'm trying to get external functions working with PostgreSQL 7.2.1 under
MacOS X. I am using Marc Liyanage's installer package
(http://www.entropy.ch/software/macosx/postgresql/). Aside from being
unable to find postgres.h to include, I can't load any libraries at all.
Any attempt, whether with CREATE FUNCTION ... LANGUAGE C or simply LOAD,
gives the same message. For example, if I try to load libSystem:

ERROR:  Load of file /usr/lib/libSystem.dylib failed: no error message available

Has anyone managed to get external functions working under MacOS X?

--Greg