Summary

1. NDR is now enforced on ARMv7/ARM64 instead of bombing out with an error.
2. Make GCC/Clang not use anything in the red zone on x64 for now.
3. Compile with -fno-omit-frame-pointer on x64 as well.
4. More comments for non-commented machine code.
5. Don't attempt saving/restoring RSI and RDI outside Windows since both are volatile in the System V ABI.

Checklist

• I have discussed this with core contributors already
• This pull request requires changes to the ROM set
  • I have opened a roms pull request - https://github.com/86Box/roms/pull/changeme/

References

None.