Turns out the inlining behavior of `const` variables at global scope
that we've been relying on lately is actually exclusive to C++ mode…
once again!
Part of P0133, funded by [Anonymous].
The TH04 one might have the same function structure, but the only thing
that's actually identical in both games is the picture darkening loop.
Part of P0119, funded by [Anonymous] and -Tom-.
The pascal calling convention for TH03's input mode functions actually
sort of matters, since we have this nice function pointer type that
expects pascal.
nmlgc