This commit cleans up and generalises the Makefile, adds support for
variants (following the unix port) and adds the "standard" variant as the
default variant.
Signed-off-by: Damien George <damien@micropython.org>
When enabled the GC will not reclaim any memory on a call to
`gc_collect()`. Instead it will grow the heap.
Signed-off-by: Damien George <damien@micropython.org>
This simplifies the config file. This is not a no-op, it does enable a few
new features to bring the port in line with this config level.
Signed-off-by: Damien George <damien@micropython.org>