* regex.c [emacs] (ISALNUM, ISALPHA, ISPUNCT): Don't depend on locale
[emacs] (ISASCII): Don't define ISASCII in this case.
(IS_REAL_ASCII): New macro, 2 alternate definitions.
(ISUNIBYTE): Likewise.
[emacs] (ISDIGIT, ISCNTRL, ISXDIGIT, ISGRAPH, ISPRINT):
Don't use ISASCII.
* regex.c: Handle new class names `ascii', `nonascii',
`unibyte, `multibyte'.
(BIT_ASCII, BIT_NONASCII, BIT_UNIBYTE, BIT_MULTIBYTE): New macros.
(IS_CHAR_CLASS): Accept new class names.
(regex_compile, re_match_2_internal): Handle the new classes.