Agreed! 

The way I see it there are two separate issues here:

1. Going forwards in general how should the `qt` formula best handle the `--without-ssse3` flag
2. In light of the current Haswell bug, how should the formula be adapted to get it working on Haswell Macs

I think the answer to 1 is as you said before, something along the lines of

     if build.without?('ssse3') || ! Hardware::CPU.ssse3

(hope `!` is `not` in Ruby! :P) 

As for 2, in the short term we adopt the formula to include the haswell check.

If the Qt guys aren't already aware of this, they should be notified of the ssse3 haswell issue, as it seems to be independent (or a complication of) the broader issues of getting qt4 compiled on 10.9. Once it's fixed on their end the formula can drop the `:haswell` check, just as the formula won't forever include your manual patching of the qt source.

If we separate out these two concerns here and leave the haswell bug flagged (I don't know how homebrew deals with such scenarios, an open issue perhaps?) and clearly documented that seems the best way forwards to me.