python3.6 on ubuntu

[Patrick Welche <prlw1%cam.ac.uk@localhost>]

After a make clean in lang/python3.6 which is at version 3.6.6, on ubuntu 16.04:

Listing '/home/prlw1/pkgsrc/lang/python36/work/.destdir/home/prlw1/pkg/lib/python3.6/site-packages'...
PYTHONPATH=/home/prlw1/pkgsrc/lang/python36/work/.destdir/home/prlw1/pkg/lib/python3.6 LD_LIBRARY_PATH=/home/prlw1/pkgsrc/lang/python36/work/Python-3.6.6  ./py
thon -E -m lib2to3.pgen2.driver /home/prlw1/pkgsrc/lang/python36/work/.destdir/home/prlw1/pkg/lib/python3.6/lib2to3/Grammar.txt
Generating grammar tables from /home/prlw1/pkgsrc/lang/python36/work/.destdir/home/prlw1/pkg/lib/python3.6/lib2to3/Grammar.txt
Writing grammar tables to /home/prlw1/pkgsrc/lang/python36/work/.destdir/home/prlw1/pkg/lib/python3.6/lib2to3/Grammar3.6.5.final.0.pickle
                                                                                                                     ^^^^^

$ bmake show-var VARNAME=PKGVERSION
3.6.6
$ work/Python-3.6.6/python --version
Python 3.6.5                          <--------------!!!!!!
$ ls -l work/Python-3.6.6/python
-rwxrwxr-x 1 prlw1 prlw1 13144 Jul 31 15:10 work/Python-3.6.6/python

which is different to the currently installed pkg/bin/python3.6 which is
indeed 3.6.5, so can't be a copy.

Puzzled...

Patrick