Log Message:
mate-system-monitor: fix builds

Being the lone MATE 1.22 hold-out in pkgsrc, this package really does
still need intltool to build, so add it here now that it's been removed
from meta-pkgs/mate/Makefile.common. This build failure wasn't noted
before, as this package isn't built by the meta package. (There's been
a 1.24.1 version released, but it requires libgtop >= 2.37.2, while we
still have 2.28.4 in pkgsrc. Updating libgtop is not trivial, given the
number of patches for NetBSD, FreeBSD, DragonFly, Darwin, SunOS, and
possibly more.)