iswalnum_l: iswnumber_l() isn't in 1003.1-2008 either.
Document wcscoll_l() and wcsxfrm_l().
We don't have wcscasecmp_l() and wcsncasecmp_l(), so #if 0 prototypes.
Improve various ctype.h manual pages.

Mention the *_l() functions in descriptions, return type information etc.,
and additional other improvements.