See the original thread for details on how to accomplish this should you be interested in this solution. This is a bit of work and you need to get some developer tools first: Xcode and MacPorts.
If you don't have a backup or want to have the newest client anyhow, you need to compile the missing newer version of libc++. Now it doesn't update the Steam app, but games still update. I have the file in both places now, but I'm pretty sure it only needs to be in that last one.
So I copied it into the Steam Application by right-click Steam -> Show Package Contents -> open Contents -> open MacOS -> put the file in there. At 1st, I put it in ~/Library/Application Support/Steam/SteamApps/ but that didn't work. Originally posted by jerry.barrington:Use a text editor, and make a file with one line:
