ctype and gcc9

[Patrick Welche <prlw1%cam.ac.uk@localhost>]

Since gcc9, essentially every ctype using piece of software fails with

   error: array subscript has type 'char' [-Werror=char-subscripts]

which prompts a style question: cast every argument of every call to
a ctype function in every piece of software to (unsigned char), or
-Wno-error=char-subscripts], or something else?


Cheers,

Patrick