ERC tracking broken

[Antoine Levitt]

ERC tracking seems to be broken. Reverting to the binary of emacs I
compiled yesterday fixes it, so I strongly suspect it's a result of

commit 5e4cb836580a8ef2f9ea9b4b8317005941920027
Author: Stefan Monnier <address@hidden>
Date:   Mon Mar 28 16:26:35 2011 -0400

    Don't reset post-command-hook to nil upon error.

which interferes with a patch by Julien Danjou about using
post-command-hook to notice window changes in erc-track. I don't
remember the specifics though.

Also, it seems it has broken ido completion, but I'm not sure exactly
how and it might be related to custom settings I have. The ERC thing
seems easier to debug.