Si has instalado MacPorts y te olvidaste instalar antes Xcode puedes desinstalarlo fácilmente con el siguiente código desde la terminal
%% sudo rm -rf \
/opt/local \
/etc/manpaths.d/macports \
/etc/paths.d/macports \
/Applications/DarwinPorts \
/Applications/MacPorts \
/Library/LaunchDaemons/org.macports.* \
/Library/Receipts/DarwinPorts*.pkg \
/Library/Receipts/MacPorts*.pkg \
/Library/StartupItems/DarwinPortsStartup \
/Library/Tcl/darwinports1.0 \
/Library/Tcl/macports1.0