improve ctype.h macros to diagnose errors
improve ctype.h macros to diagnose errors

the casts of the argument to unsigned int suppressed diagnosis of
errors like passing a pointer instead of a character. putting the
actual function call in an unreachable branch restores any diagnostics
that would be present if the macros didn't exist and functions were
used.

chardi/musl,chardi/musl,chardi/musl