This executor has the advantage of being able to work correctly when
there are Ruby stack frames underneath C/C++ stack frames in the stack.
Still need to implement handling Ruby fibers.
We can't have them as normal functions because reentrant calls into the
Ruby API don't work if you do that, i.e. calling into the Ruby API and
that calls mkxp-z's bindings and that calls back into the Ruby API.
The old arguments were invoking undefined behaviour that may or may not
cause crashes when initializing Ruby depending on which path on the
build machine Ruby was built on!
WebAssembly is little-endian regardless of what machine you run it on,
so the WebAssembly implementation needs to know if the machine is
big-endian or little-endian to function properly.
Right now I've implemented opening game files that are in zip format and
added a filesystem implementation to allow reading the game files. I've
also added a `Dir.glob` call core.cpp to print the contents of the root
directory of the game zip file to the log as a test.
