* libc/ctype/ctype_.c: Add new pointer __ctype_ptr__ which is one
less than the old __ctype_ptr.
* libc/ctype/isalnum.c: Use __ctype_ptr__.
* libc/ctype/isalpha.c: Ditto.
* libc/ctype/iscntrl.c: Ditto.
* libc/ctype/isdigit.c: Ditto.
* libc/ctype/islower.c: Ditto.
* libc/ctype/isprint.c: Ditto.
* libc/ctype/ispunct.c: Ditto.
* libc/ctype/isspace.c: Ditto.
* libc/ctype/isupper.c: Ditto.
* libc/ctype/isxdigit.c: Ditto.
* libc/include/ctype.h: Change ctype macros to use new __ctype_ptr__
and add declaration of __ctype_ptr__. Remove older ctype table pointers
from here even though they can still work.
