systems. There are no changes to the xpmroot program itself, really, but
since fvwm2 is now at version 2.2.2, there is no reason to fetch and keep
two distinct versions of the fwvm2 distfile.
Implement a new DEPENDS definition, which looks for an installed
package, building it if not present, and use it in preference to
LIB_DEPENDS. This should make the package collection more useful on
NetBSD ELF ports.
