received complaints about using shorts in the table (but i need a range
of -1..255), so now the tables will not be used unless either toupper()
or tolower() (and soon, setlocale()) are used. This can save up to 514
bytes.
In toupper_.c and tolower_.c make sure that our assumption of EOF == -1
holds.
Fixed bug where _toupper_tab_ was initialized pointing to _C_tolower_tab.