Bug#433671:

[Victor Luchits]

Filenames for game modules need the arch suffix so that they can be
distinguished at load time. All game modules for all archs are packed
into a single .pk3 file which is used for "pure" servers. Clients that
connect to "pure" servers are forced to download, unpack this .pk3 and
load the game modules of their arch. A typical modules.pk3 file (which
is essentially a .zip file) looks something like this:

game_x86.dll
game_x64.dll
game_x86.so
game_x86_x64.so
...

-- 
Best regards,
 Victor Luchits