Log Message:
audio/flactag: Fix DragonFly breakage

patch-aa was the main reason this package broke on DragonFly.  Probably the
__NetBSD__ macro should have been used from the beginning (since pkgsrc
serves multiple platforms), but rather than risk breaking flactag on other
platforms, I've chosen to use __DragonFly__ macro to restore the original
code.

Also, -lintl is needed by DragonFly, so the gettext-lib was added the the
buildlink3 list.