gettext

0b0047d6 - xgettext: Avoid error 'present charset "CHARSET" is not a portable encoding name' when possible.

xgettext: Avoid error 'present charset "CHARSET" is not a portable encoding name' when possible. Reported by Arsen Arsenović <arsen@aarsen.me> at <https://savannah.gnu.org/bugs/?64490>. This changes the behaviour back to the one from gettext 0.21.1, where this xgettext invocation produced just a warning. * gettext-tools/src/msgl-iconv.c (iconv_message_list_internal): Don't give an error when a PO file has a header entry with charset=CHARSET and is entirely ASCII. * gettext-tools/src/msgl-cat.c (catenate_msgdomain_list): Likewise. * gettext-tools/tests/xgettext-combine-1: New file. * gettext-tools/tests/xgettext-combine-2: New file. * gettext-tools/tests/xgettext-combine-3: New file. * gettext-tools/tests/Makefile.am (TESTS): Add them.