Most discs only use the "raw" device, but it turns out the Haiku installation
"anyboot" images don't, and those would fail to detect here. If there's
some multi-partition disc thing and the OS mounted each separately, we should
report each of them.
So now you can drop this into your program and not worry about filename
conflicts, or where "platform_unix.c" came from in the debugger, etc.
Also renamed the "beos" sources to "haiku" and "macosx" to "macos" to match
modern platform names.
Ryan C. Gordon