With regard to ctype, digits (e.g. 0 to 9) and xdigits (the 0 to 9 portion
of hexidecimal numbers) are all considered "numbers". (Note that while
all digits are numbers, not all numbers are digits).

Enhance localedef to automatically set the "number" characteristic when
it encounters a digit or xdigit definition. This fixes malfunctionning
isalnum(3)

Obtained from: DragonflyBSD