It would be nice to check if we can connect via the Unix socket and default to 127.0.0.1 if we can't. Haven't come up with some way to do that yet though.

It's been marked as bogus

This is due to IPv6 Support in windows at least (http://blogs.iis.net/donraman/archive/2010/06/11/php-5-3-and-mysql-connectivity-problem.aspx (Linked in the above report)), Do Linux systems also have the same issue and we just haven't picked up on it?

Fixing summary (my fault anyway), this is about $wgDBhost, not about $wgServer.

WONTFIX. Tweaked some help info in r72664, though.

See the commit and help tweak for more info.