Changes are:
- string0 is no longer built when building for host as the target, because
it'll be provided by the system libc and may in some cases clash with the
system one (eg on OSX).
- mp_int_t/mp_uint_t are defined in terms of intptr_t/uintptr_t to support
both 32-bit and 64-bit builds.
- Configuration values which are the default in py/mpconfig.h are removed
from mpconfigport.h to make the configuration a bit more minimal, eg as
a better starting point for new ports.
8e591d412a