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.
Some tools do not support local/static symbols (one example is GNU ld map file).
Exposing all functions will allow to do detailed size comparisons, etc.
Also, added bunch of statics where they were missing, and replaced few identity
functions with global mp_identity().
__bool__() and __len__() are just the same as __neg__() or __invert__(),
and require efficient dispatching implementation (not requiring search/lookup).
type->unary_op() is just the right choice for this short of adding
standalone virtual method(s) to already big mp_obj_type_t structure.
mp_obj_int_get() can be used when just full resolution of C machine_int_t
is required (returns truncated value of long int). mp_obj_int_get_checked()
will throw exception if Python int value not representable in machine_int_t.
