xorg-*proto ports and system_x11

[Jeremy Huddleston]

> Yeah... it just really complicates things on Tiger with +system_x11  
> if we start pruning out header files that are already available.   
> For example, libAppleWM has stayed the same, but the protocol  
> headers have been updated to add new functionality that is necessary  
> for the new server.
>
>> I am far from an expert on X11, but it seems to me that we either  
>> need to
>> add a system_x11 variant to the proto ports or trim down the  
>> dependencies
>> of the current system_x11 ports.

> I'd be fore that once the variant-aware dependencies are in order,  
> so we could say things like depends_build port:xorg-applewmproto:- 
> system_x11 or whatever the syntax would be.

Actually, the protocol headers should be pulled in by the ports  
needing them, not the libs, so my example above is invalid because  
xorg-server itself needs the new applewmproto, but libAppleWM does not.

I pushed your patch from http://trac.macports.org/ticket/18098 which  
removes the dependencies from the libs when +system_x11