It wasn't being used at all. Let's remove it.
Use isdigit(3) directly in comments that referenced it.
Also, in those comments, remove an outdated reference to the fact
that ISDIGIT_LOCALE(c) might evaluate its argument more than once,
which could be true a few commits ago, until
IN_CTYPE_DEFINITION(c) was removed. Previously, the definition
for ISDIGIT_LOCALE(c) was:
#if defined (STDC_HEADERS) || (!defined (isascii) && !defined (HAVE_ISASCII))
# define IN_CTYPE_DOMAIN(c) 1
#else
# define IN_CTYPE_DOMAIN(c) isascii(c)
#endif
#define ISDIGIT_LOCALE(c) (IN_CTYPE_DOMAIN (c) && isdigit (c))
Which could evaluate 'c' twice on pre-C89 systems (which I hope
don't exist nowadays).
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
44126d85ee