Installation directory best practices

[Babak Farrokhi]

> 
> I tend to use WWWDIR (which excludes PREFIX); but as you say, there is
> no consistency amongst ports.
> 
[Babak Farrokhi] 
It is perhaps a good idea to add WWWDIR variable to bsd.port.mk and add a
hint to porters-handbook so that all web apps are preferred to install in
WWWDIR. It would also be nice if portlint(1) complains if a port installs
directly into www/data or www/data-dist.