Recent M1 SoC can be supported by bumping gcc to a recent
version with macOS arm support.
Tweak the Makefile and compile flags to build succesfully
for this new architecture.
Fix compiled SDCC binaries by removing program-prefix
SDCC binaries are prefixed with `z80-neogeo-ihx`, which breaks
aslink and sdar. Replace those binaries with shell-script wrappers
bin/z80-neogeo-ihx-<tool> that exec into z80-neogeo-ihx/bin/<tool>
Also clean up the installation of unneeded 8bits SDCC backends.
When targeting native Win10 via MSYS2, the Makefile currently
supports building mingw64 environment (native Win10 based on
the legacy msvcrt C runtime).
Tweak the Makefile configuration to also support the ucrt64
environment (native Win10 based on the new ucrt C runtime).