Problems reported by Daniel Richard G. in
http://lists.gnu.org/archive/html/bug-gnulib/2015-09/msg00020.html
* lib/c-ctype.c: Include <limits.h>, for CHAR_MIN and CHAR_MAX.
Include "verify.h".
(C_CTYPE_ASCII, C_CTYPE_CONSECUTIVE_DIGITS)
(C_CTYPE_CONSECUTIVE_LOWERCASE, C_CTYPE_CONSECUTIVE_UPPERCASE):
Define as enum constants with value false, if not defined, so that
code can use 'if' instead of 'ifdef'. Using 'if' helps make the
code more portable, as both branches of the 'if' are compiled on
all platforms.
(C_CTYPE_EBCDIC): New constant.
(to_char): New static function.
(c_isalnum, c_isalpha, c_isdigit, c_islower, c_isgraph, c_isprint)
(c_ispunct, c_isupper, c_isxdigit, c_tolower, c_toupper):
Rewrite to use 'if' instead of 'ifdef'.
Use to_char if non-ASCII. Prefer <= to >=.
Prefer true and false to 1 and 0, for booleans.
(c_iscntrl): Use 'if', not 'ifdef'. Special case for EBCDIC.
Verify that the character set is either ASCII or EBCDIC.
* tests/test-c-ctype.c: Include <limits.h>, for CHAR_MIN
(to_char): New function.
(test_all): Port to EBCDIC. Add some more tests, e.g., for c_ispunct.