We don't use ChangeLogs and the LINGUAS file is replaced by the AS_ALL_LINGUAS m4 macro.
Use the one that ships with gtk+.
The P_() macro adds a context for the property nick and blurb. In order to make xgettext recognize it, we need to drop glib-gettexize inside the autogen.sh script and ship a modified Makefile.in.in with Clutter.