[arch-haskell] Enabling profiling (-p) option for AUR packages

[Linus Arver]

Hi Peter,

So it's been about a week now, and the discussion has more or less
settled. I've sent a pull request on github detailing everything. For
those on the ML, it is:

https://github.com/archhaskell/archlinux/pulls

It turns out that the archlinux repo (and not cabal2arch) is the one
responsible for the default PKGBUILD text that we were discussing.

I will update the Arch Wiki as necessary once the changes are pulled.

-Linus