pyoxidizer: allow extensions to be loaded from the file system
It seems that setting this config is all that's needed to be able to
load extensions from the file system (which we clearly want). Thanks
for making this work, Gregory Szorc!.
Differential Revision: https://phab.mercurial-scm.org/D8122
#require docutils gettext
$ $TESTDIR/check-gendoc da
checking for parse errors