You need something like this:
* "tce-load -i compiletc python3.6-dev"
* "wget [source tarball]"
* "tar xf [source tarball]"
* "cd [source]"
* "python3.6 setup.py build"
* "mkdir /tmp/pkg"
* "sudo python3.6 setup.py install --root=/tmp/pkg"
Then remove the "__pycache__" subdirectories from /tmp/pkg/usr/local/lib/python3.6/site-packages (they are several layers deep)
* "cd /tmp"
* sudo mksquashfs pkg/ python3.6-[source].tcz