Restore a fixed version of patch-ah.  While -R was in the string, it
was there because guile was built against gmp etc. from /usr/pkg, not
present to let programs find -lguile.  Therefore, add in rpath for
$(libdir) when we add in -L for libdir.

This looks ok to me, but I will be away AFK most of the day, so feel
free to remove the line in distinfo and re-commit if this turns out to
be bad.

(gdt)