New module 'wmemcmp'. * modules/wmemcmp: New file. * lib/wchar.in.h (wmemcmp): New declaration. * lib/wmemcmp.c: New file. * lib/wmemcmp-impl.h: New file, from libutf8 with modifications. * m4/wmemcmp.m4: New file. * m4/wchar_h.m4 (gl_WCHAR_H): Test whether wmemcmp is declared. (gl_WCHAR_H_DEFAULTS): Initialize GNULIB_WMEMCMP, HAVE_WMEMCMP. * modules/wchar (Makefile.am): Substitute GNULIB_WMEMCMP, HAVE_WMEMCMP. * tests/test-wchar-c++.cc: Test the declaration of wmemcmp. * doc/posix-functions/wmemcmp.texi: Mention the new module.

# wmemcmp.m4 serial 1
dnl Copyright (C) 2011 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.

AC_DEFUN([gl_FUNC_WMEMCMP],
[
  AC_REQUIRE([gl_WCHAR_H_DEFAULTS])
  AC_CHECK_FUNCS_ONCE([wmemcmp])
  if test $ac_cv_func_wmemcmp = no; then
    HAVE_WMEMCMP=0
    AC_LIBOBJ([wmemcmp])
  fi
])