SDK v8.0.1

Bug fixes

• llvm-mos/llvm-mos#413 - Fixed compiler crash due to new shift chaining optimization.
• Fixed latent issue in register scavenger; it would attempt to scavenge X, but this isn't implemented. Instead, disable ZP, Y addressing to avoid the case.
• Fixed recursive codegen issue uncovered in the register scavenger; since it can run more than once, we need to check if the reserved imaginary save registers are in use before marking a register for scavenging.
• #247 - Fix pce_joypad_read() only returning low nibble - @asiekierka

Optimizations

• #248 - Base printf routines on one another. Helps decrease code size when multiple printf variants are used.

Miscellaneous

• #246, llvm-mos/llvm-mos#412 - Add arm64 build target for macOS
• #241 -- Use emutest and libretro to test arbitrary emulators in Github CI (currently only NES and Atari2600 are implemented) - @sehugg
• Merge llvm/llvm-project@f4c6947