Is there an easy way to find out which port loads which library?

[Bernard Higonnet]

Hello,

Every once in a while, I have trouble installing a port and the problem 
is either a missing library, an obsolete library, or some kind of 
problem seemingly associated with a library.

Is there a simple, direct, complete, and unequivocal way to find out 
which port(s) install which libraries?

When I do have one of these problems I search for info on the problem 
and most often get some information, often peripheral to my problem but 
which at least helps me...

TIA
Bernard Higonnet