Short bug report:
When installing PgSQL into a non-standard location (like /opt/foo) the
configure script decides to install all the contrib libraries and
plpglsq into /opt/foo/lib/postgresql. This would be fine, except that
backend does not recognize this directory as a place to be searched for
$libdir (perhaps it is referencing the $libdir macro instead of the
$pkglibdir macro?). So tools like 'createlang' fail, and loading .sql
files that reference things like $libdir/libfoo.so also fail.
Paul