Ports/.port_include.sh, Toolchain/BuildIt.sh, Toolchain/UseIt.sh
have been left largely untouched due to use of Bash-exclusive
functions and variables such as $BASH_SOURCE, pushd and popd.
We were installing libraries into /Libraries/Root, rather than in /Root.
This made the ports system behave rather unpredictable, since I had old
versions of things in /Root and new versions of things in /Libraries/Root.