Wanted_stuff is stuff path for your $WANTED packages stuff. I add it to libpostgresql (and tazwok) cause this way we don't need to copy the files to $src since they could be deleted before the wanted packages are made with cooker. You need add support for this in to cook. Here is the code:
[ "$WANTED" ] && wanted_stuff="$WOK/$WANTED/stuff"
There are cases where you need stuff folder from wanted packages. Can't remember which ones but this is better then copying files to source folder. You need to add $wanted_stuff to be compatible with tazwok anyway.
# FIXME: tazwok specific code (if aufs is cooked you dont need to get-src)
You need aufs to compile after linux cause its depend on linux-modules-headers. The version could be different then the one your building from. Ex. using linux-modules-headers 2.6.37 when your building linux 2.6.38.