There are ON/Userland cross consolidation dependencies.
The GNU gettext compatible feature currently supported by
the gettext() functions in libc from the ON consolidation is
based on the GNU MO format version 1.0, which matches the
one that the GNU gettext 0.16.1 package supports.  Whenever
the GNU MO format version gets changed by updating the GNU
gettext package in Userland, an appropriate update is also
required to the gettext() functions in libc, and vice versa.
For details, see the following PSARC cases:
PSARC/2007/634 More compatibility with GNU gettext
               in gettext(3c)
PSARC/2007/635 GNU gettext 0.16.1
PSARC/2013/346 GNU gettest 0.18.3 (updated to 0.19.3)