volatile variants (was Re: Gimp 2.6 & Pango 1.8 : no font rendering)

[David Evans]

Ryan Schmidt wrote:
> If you want some undefined build that contains support for no graphics 
> output at all, you use just +no_x11. :) Hmm, maybe I need to make that 
> impossible.
Actually cairo with just +no_x11 still  has several backends available.  
For instance, you can render SVG, PDF, PNG, etc to a file.

In addition, I think the documentation should stress the pitfalls of - 
variants (like -x11) since they aren't handled well by MacPorts.  It would
work better if ports with default variants would just make the 
equivalent actions part of the default behavior of the port and provide 
+no_whatever variants to
remove a particular default behavior if desired.