Macintosh versions of GR and MH1-2 use the same combined directory
filename convention as DOS, Atari ST and Apple IIgs (but not Amiga or
CoCo3). However, the filename convention for volumes uses the common
AGI v2 format, without a game id prefix.
Example:
DOS: GRDIR, GRVOL.x
Mac: GRDIR, VOL.x
To account for this, we'll use the following:
1. Rather than take the directory filename prefix from volume files,
we now get this from the directory files themselves (which makes
more sense anyway).
2. Later, when loading individual volumes, check for Mac platform and
exclude the prefix from the path.
This improves the previous single game check for Mac Gold Rush, which
formed directory and volume paths for that game only. This check is
now obsolete and has been removed. The detection flag that was used to
invoke the workaround has also been removed.
- These structs are necessary for detection, as well as the engine itself.
- So, we move it to a common header file, include it once in both the files.
- This way, we won't have to include agi.h inside detection translation unit, which saves us much junk code going into the executable.