Mupen64Plus 256MB build system

I created this script to compile Mupen64Plus across various platforms in one go, notably adding compatibility for B3313 and other large romhacks.

Improvements are welcome!

Features:

• Android build needs to be dockerized
• Nintendo Switch build needs to be added (I just gave up on a pointer mismatch in the upstream code for now, as I remember it taking ages to get it built)
• If possible, feel free to add other systems (Mac OS, iOS, etc) or Mupen variants as well

Fixes:

• Performance improvements (for the build process, or for the built binaries)
• Anything that's broken (incompatibilities, etc)