Running glib-gettextize from glib-2.14.6 (and back at least to 2.12.12) built into prefix=/sw on OS X 10.4 gives me:

Creating po/ subdirectory
Symlinking file mkinstalldirs
Symlinking file po/Makefile.in.in

Please add the files
  codeset.m4 gettext.m4 glibc21.m4 iconv.m4 isc-posix.m4 lcmessage.m4
  progtest.m4
from the /aclocal directory to your autoconf macro directory
or directly to your aclocal.m4 file.
You will also need config.guess and config.sub, which you can get from
ftp://ftp.gnu.org/pub/gnu/config/.

Bug: tells me to use "/aclocal" (coded as "$datadir/aclocal" in the script) instead of "/sw/share/aclocal" or whatever prefix-based location is appropriate. The bug is that glib-gettextize declares:

datadir=${datarootdir}
datarootdir=${prefix}/share

based on the glib-gettextize.in template:

datadir=@datadir@
datarootdir=@datarootdir@

but this is shell, not makefile, so $datarootdir is blank when it's used to define $datadir. Should instead be:

datarootdir=${prefix}/share
datadir=${datarootdir}

Those @datadir@ and @datarootdir@ values are the autoconf defaults, so should just switch them in the .in (i.e., if user is overriding with ./configure flags, he already knows what he's setting).