localcharset tests: Test in the UTF-8 environment on native Windows. * m4/windows-rc.m4: New file. * tests/test-localcharset-w32utf8.sh: New file. * tests/test-localcharset-w32utf8.c: New file. * tests/windows-utf8.rc: New file. * tests/windows-utf8.manifest: New file. * modules/localcharset-tests (Files): Add these files. (Depends-on): Add test-xfail. (configure.ac): Invoke gl_WINDOWS_RC. (Makefile.am): Arrange to compile test-localcharset-w32utf8 and run test-localcharset-w32utf8.sh.