gettext-runtime/intl/setlocale.c: Add fixes from gnulib.

gettext-runtime/intl/setlocale.c: Add fixes from gnulib.

2018-08-11  Bruno Haible  <bruno@clisp.org>

        setlocale: Trivial simplification.
        * lib/setlocale.c (setlocale_unixlike): Remove redundant #if.

2017-04-21  Bruno Haible  <bruno@clisp.org>

        Fix test-mbrtowc5.sh failure on native Windows.
        * setlocale.c (setlocale_unixlike): Accept "POSIX" as an alias for
        "C".

2016-03-22  Geert Janssens  <janssens-geert@telenet.be>

        setlocale: add "sv" to Windows language table
        * setlocale.c (language_table) [W32]: Add "sv".
        Reported in <https://savannah.gnu.org/bugs/?44588>.

2012-01-04  Bruno Haible  <bruno@clisp.org>

        Talk about "native Windows API", not "Win32".
        * setlocale.c: Update comments to mention native Windows.