Why was the cd command removed?
The cd command was removed from trunk in r28796. As of release 1.7.0 it is no longer available for use in Portfiles. cd is harmful as it changes the current directory of the whole process and not only of the current Tcl interpreter. Also, it becomes unreliable when used inside phases and other phases begin to rely on it. Please use absolute paths instead, starting with ${worksrcpath}. If you need to run a command with system, use it like system “cd ${worksrcpath} && autoreconf”.