Your output shows that rev-upgrade determined that libgcc was broken, and then failed to rebuild it. According to the log, the first reasons the build failed are:
:info:build /macports/var/macports/build/_macports_var_macports_sources_rsync.macports.org_release_tarballs_ports_lang_gcc48/libgcc/work/build/x86_64-apple-darwin11/libstdc++-v3/include/bits/stl_algobase.h:1000:27: error: 'signed' and 'unsigned' specified together for '__n'
:info:build __lg(unsigned long long __n)
:info:build ^
:info:build /macports/var/macports/build/_macports_var_macports_sources_rsync.macports.org_release_tarballs_ports_lang_gcc48/libgcc/work/build/x86_64-apple-darwin11/libstdc++-v3/include/bits/stl_algobase.h:1000:30: error: 'signed' and 'unsigned' specified together for '__lg'
:info:build __lg(unsigned long long __n)
:info:build ^
It might be interesting to know why rev-upgrade thinks libgcc is broken. Is it shown in the output of "port outdated
"? What does "sudo port -v rev-upgrade
" show?