Log Message:
Build Python with thread support by default and turn the existing
python*-pth packages into meta-packages which will install the non-pth
packages. Bump PKGREVISIONs on the non-pth versions to propagate the
thread change, but leave the *-pth versions untouched to not affect
existing installations.
Sync all PYTHON_VERSIONS_AFFECTED lines in package Makefiles.