Type representing signed size doesn't have to be int, so use special value
which defaults to SSIZE_MAX, but as it's not defined by C standard (but rather
by POSIX), allow ports to set it.
Blanket wide to all .c and .h files. Some files originating from ST are
difficult to deal with (license wise) so it was left out of those.
Also merged modpyb.h, modos.h, modstm.h and modtime.h in stmhal/.
I'm pretty sure these are never reached, since NOT_EQUAL is always
converted into EQUAL in mp_binary_op. No one should call
type.binary_op directly, they should always go through mp_binary_op
(or mp_obj_is_equal).
With the implementation of proper string formatting, code to print a
small int was delegated to mpz_as_str_inpl (after first converting the
small int to an mpz using stack memory). But mpz_as_str_inpl allocates
heap memory to do the conversion, so small ints needed heap memory just
to be printed.
This fix has a separate function to print small ints, which does not
allocate heap, and allocates less stack.
String formatting, printf and pfenv are now large beasts, with some
semi-duplicated code.
Mostly just a global search and replace. Except rt_is_true which
becomes mp_obj_is_true.
Still would like to tidy up some of the names, but this will do for now.