ioquake3.x86_64.exe can't load x86 OpenAL32.dll. Using separate
library names allows shipping OpenAL for both architectures.
Though since the dll name is saved in the config file, using both
clients on the same computer will cause one client arch to always
try to load the wrong OpenAL dll and then fallback to the correct
default OpenAL dll. I guess it could be fixed by using separate
cvar names for s_alDriver.
MSYS2 and some mingw builds use mingw64 instead of mingw32. If you run
`make installer` from the top-level, PLATFORM should be set correctly
when building the installer.
