Printing debugging info by defining MICROPY_DEBUG_VERBOSE expects
a definition of the DEBUG_printf function which is readily available
in printf.c so include that file in the build. Before this patch
one would have to manually provide such definition which is tedious.
For the msvc port disable MICROPY_USE_INTERNAL_PRINTF though: the
linker provides no (easy) way to replace printf with the custom
version as defined in printf.c.
Add some features which are already enabled in the unix port and
default to using the Python stack for scoped allocations: this can be
more performant in cases the heap is heavily used because for example
the memory needed for storing *args and **kwargs doesn't require
scanning the heap to find a free block.
For MSVC off_t is defined in sys/types.h but according to the comment
earlier in mpconfigport.h this cannot be included directly.
So just make off_t the same as mp_off_t.
This fixes the build for MSVC with MICROPY_STREAMS_POSIX_API
enabled because stream.h uses off_t.
This is to keep the top-level directory clean, to make it clear what is
core and what is a port, and to allow the repository to grow with new ports
in a sustainable way.
