MINIX libc headers define the ctype.h toupper() etc. functions as
preprocessor macros that don't cast their argument to int! So a char
argument causes clang to say "warning: array subscript is of type
'char'".
Nowadays compilers have good optimizers that know when to inline static
functions depending on the user's chosen optimization level (and speed vs size
optimization). We don't need to annotate functions manually.
For number types, we rely on classic C types (char, short, int, long) to be
the correct sizes. For precise bit widths, use standard intN_t and uintN_t.
For size_t, just use system size_t.
Lassi Kortela