c32is*: Ensure GNULIB_defined_mbstate_t is defined on AIX. * m4/mbrtowc.m4 (gl_MBSTATE_T_BROKEN): Define through AC_DEFUN_ONCE. * m4/mbrtoc32.m4 (gl_FUNC_MBRTOC32): Require it. * modules/c32isalnum (Files): Add m4/mbrtowc.m4, m4/locale-ja.m4. (configure.ac): Require gl_MBSTATE_T_BROKEN. * modules/c32isalpha: Likewise. * modules/c32isblank: Likewise. * modules/c32iscntrl: Likewise. * modules/c32isdigit: Likewise. * modules/c32isgraph: Likewise. * modules/c32islower: Likewise. * modules/c32isprint: Likewise. * modules/c32ispunct: Likewise. * modules/c32isspace: Likewise. * modules/c32isupper: Likewise. * modules/c32isxdigit: Likewise.