With the upcoming `#include` cleanup, it finally makes sense to split
off all graphics-related code into its own header. In turn, it makes
more sense to store all of these future master.lib headers in, well,
the master.lib directory, which provides a new 8 characters for their
file names. Turns out that the rationale I gave for the root directory
placement in 8266bbd didn't hold up 3½ years later…
(Also, the `pc98.h` declarations will eventually be split into
`game/coords.hpp` and something in `platform/x86real/pc98/`.)
Part of P0284, funded by [Anonymous] and Blue Bolt.
Ah, the first time I encountered Q12.4 subpixels, way back in early
2018… I'd like this to be the final piece of code decompiled in either
of these games, but its data needs to be moved to C land now since it
blocks the Music Room.
And yes, we even have to compile this one twice.
Part of P0263, funded by [Anonymous].
nmlgc