Ambiguous python version in waf

[Guido Aulisi]

Hi,
according to latest python guides, we should avoid calling generic
unversioned python command
(https://fedoraproject.org/wiki/Changes/Avoid_usr_bin_python_in_RPM_Build#...)

But what should we do if it's called inside waf? waf is provided
upstream, should we patch it to call either python2 or python3, or use
PYTHON_DISALLOW_AMBIGUOUS_VERSION=0?

I got this problem in recent ardour5 rawhide builds
(https://apps.fedoraproject.org/koschei/package/ardour5?collection=f28).
Now I'm seeing that builds are back to normal and python2 has been downgraded.

Thanks

Guido Aulisi
FAS: tartina