* Makefile.am (EXTRA_DIST): Add build-aux/git-version-gen.

The commit 8137d2b4 was a wrong fix since both singular/plural
msgids may point to the same address for Qt4 plural forms.  This
reverts the commit and fix the original double-free problem in the
right way.  Thanks to Jesper Fehrlund for suggestions.
* gettext-tools/src/xgettext.c (arglist_parser_remember_literal):
Don't ignore plural argument even if ARGNUM1 equals to ARGNUM2.
(arglist_parser_done): Make a copy of best_cp->msgid_plural when
passing it to remember_a_message_plural, if it equals to
best_cp->msgid.  Also move code conversion logic earlier taking into
account of the ownership transfer of best_cp->msgid.
* gettext-tools/src/xgettext-12: Test a single argument function.

* xgettext-12: New file.
* Makefile.am (TESTS): Add new test.

After commit 6aa7b7ed in 2009, xgettext assumed that ARGNUM1 and
ARGNUM2 of -k are different.  That could cause an double-free in
exceptional cases.
Reported by Johan Liljegren in:
<https://lists.gnu.org/archive/html/bug-gettext/2014-10/msg00028.html>.
* xgettext.c (arglist_parser_remember_literal): Don't assume that
ARGNUM1 and ARGNUM2 are different.

Fixes commit a843584f.