* locale/Makefile (headers): Add bits/locale.h.
* locale/langinfo.h: Don't include <locale.h>. Include <bits/locale.h>
and use __LC_ constants instead of LC_.
* locale/locale.h: Include <bits/locale.h> and define LC_ constants
using __LC_ constants.
* locale/bits/locale.h: New file.
* locale/loadlocale.c: Include <locale.h>.
* locale/nl_langinfo.h: Likewise.
