Hi,
On Debian 4.9 I needed the following changes to build these packages:
devel/gettext/PLIST
  -${PLIST.glibc}lib/preloadable_libintl.so
lang/mono/PLIST.Linux
  +lib/mono/4.5/mcs.exe.so
It would seem to me that the mono one is legit, but I'm not so sure
what to make of the gettext one.
Sijmen