z80_env: Remove the pointer indirection from interrupt

For some reason, this was almost always working, but we were depending on
uninitialized data. There is no need for this to be a pointer so changing it to
be just a value is safe.
z80_env: Fix z80_env/z80_env_ref declarations

This was forcing lots of casting to get to the internal data structures. This
was unsafe and obscuring the flow of the code.
Style: Fix crlf issue
Style: Format code with a clang-format
pacman: Use (un)press_input instead of accessing environment directly
Clean up print statements

Lots of debugging print statements left over.
pacman: Refactor the main loop

It's beautiful now!
Fix all the compile warnings
Style: Quiet the Makefile