mail/mail-notification (that I just updated to 2.0) needs msgfmt to
build.  The msgfmt in current (0.14.4) works fine.  The one in 3.0
(0.10.35) doesn't handle one of the statements in the po files and
thus the package doesn't build.

BUILD_USES_MSGFMT didn't work, because msgfmt is present already.

So, I put in a dependency on devel/gettext.  This is suboptimal
because it will pull in gettext on current.

Is there some way to USE_TOOLS+= msgfmt and specify the required
version?  I searched the guide and couldn't figure out how.