http://bugs.winehq.org/show_bug.cgi?id=20736
--- Comment #11 from Owen Rudge owen@owenrudge.net 2009-11-19 18:18:10 --- Sorry, that patch was indeed not against the current Wine tree. Glad it works for you though.
If there are any Mac users having this problem, could you try the patch and see if you can launch L4D2 with it?