I wanted to start using some features from the latest xmonad which wasn't in
Arch Linux's repos so have started using xmonad-git and xmonad-contrib-git
from the AUR. When updating any Haskell packages these packages require
rebuilding. My steps to do this using the yaah AUR helper:
$ yaah xmonad-git
$ yaah xmonad-contrib-git
$ cd xmonad-git
$ makepkg
$ sudo pacman -U xmonad-git-...
$ cd ../xmonad-contrib-git
$ makepkg
$ sudo pacman -U xmonad-contrib-git-...
$ xmonad --recompile