Can't update MacPorts after upgrading to Mavericks
You need to update the command line tools Xcode installs. For whatever reason, Xcode doesn't seem to want to update them itself, but you can force it by running xcode-select --install. This will pop open a GUI prompt; select "Install" and let the installer do its thing. After this, MacPorts should build itself successfully. (You may need to rehash first; rehash in tcsh, hash -r in bash and zsh (I think).)