Boom! Clever segment renaming allows us to link the same .OBJ into 12
binaries.
(Well, 10 for now, due to alignment issues in TH04's OP.EXE and
MAINE.EXE.)
Part of P0138, funded by [Anonymous] and Blue Bolt.
It's not necessary for assigning `__seg` pointers to `far` ones, which
might even remove the <dos.h> dependency in some translation units.
Part of P0134, funded by [Anonymous].
Leading to slight complications in TH02's Music Room and shot type
selection menus. Thought about leaving those in C for a while, but I
still think it's worth it for the consistency we get with the VRAM
offset functions. Also, we'll have similar code for the main menus of
later games, and I'll surely won't be using C++ when starting out with
these.
Part of P0105, funded by Yanga.