Add unit test for libintl_version.
* gettext-tools/tests/intl-version-prg.c: New file.
* gettext-tools/tests/intl-version: New file.
* gettext-tools/tests/Makefile.am (TESTS): Add it.
(check_PROGRAMS): Add intl-version-prg.
(intl_version_prg_SOURCES, intl_version_prg_LDADD): New variables.
