verifying your macports

After the scare of spurious libgcc getting in the way, I'm wondering how can we verify our setups. This is when rpm-style verification and binary distros shine. Sure you can compile stuff, but what if some crap got into your PATH -- beginning with a wrong gcc? What if some other crap got into LDFLAGS or DYLD_LIBRARY_PATH or whatever? What tools are there to verify -- completeness of each port -- proper chain of dependencies of each port -- checking that no port depends on any package not built by the ports -- e.g., nothing outside /opt/local -- that each executable in /opt/local/bin will load -- what else? Cheers, Alexy