* lib/ctype.in.h: Include <locale.h>.
(isalnum_l): New declaration.
* lib/isalnum_l.c: New file.
* lib/is_l-impl.h: New file.
* m4/isalnum_l.m4: New file.
* m4/ctype_h.m4 (gl_CTYPE_H): Test for isalnum_l.
(gl_CTYPE_H_REQUIRE_DEFAULTS): Initialize GNULIB_ISALNUM_L.
(gl_CTYPE_H_DEFAULTS): Initialize HAVE_ISALNUM_L.
* modules/ctype-h (Makefile.am): Substitute GNULIB_ISALNUM_L,
HAVE_ISALNUM_L.
* modules/isalnum_l: New file.
* tests/test-ctype-h-c++.cc: Check declaration of isalnum_l.
* doc/posix-functions/isalnum_l.texi: Mention the new module.