mtree violations should be debug info, should not be fatal errors

[Ryan Schmidt]

I'm not sure I like that mtree violations are fatal errors. The ports  
that are now failing to install because of mtree violations installed  
just fine in MacPorts 1.5.0. Why should they now fail to install?  
Their content has not changed. Sure, they may be installing things in  
places they shouldn't, but why should we make the user suffer? We  
have a -t switch which informs us about forgotten dependencies in the  
port -- but this does not issue a fatal error. It's just a message  
which portfile authors can use to improve their portfiles. Maybe  
mtree violations could be handled similarly.

I'm also concerned about needing to specify in the portfile that the  
port intends to violate the mtree. For example, I'm going to have to  
add that to the php5 port, because it wants to install an apache2  
module and the apache2 layout is considered nonstandard. So just  
because I want to install one item in a weird place, I have to turn  
off the mtree violation checks in the entire php5 portfile. It would  
be nicer if port would just issue nonfatal debug messages letting us  
know exactly which files were violating the mtree. This way I could  
assure myself that my port is installing the apache2 module in a  
weird place, yes, but that everything else is being installed in sane  
locations.