Bug#972916: sagemath ftbfs with python3.9

[Graham Inggs]

Control: reopen -1

Hi

The new upload of sagemath/9.2-1 still FTBFS [1] with Python 3.9 as
default.  I've copied what I hope is the relevant part of the log
below.

Regards
Graham


[1] https://people.debian.org/~ginggs/python3.9-default/sagemath_9.2-1+build1_amd64-2020-10-27T15:56:32Z.build


make[2]: Entering directory '/<<PKGBUILDDIR>>'
mkdir -p debian/tmp
mv sage/local debian/tmp/usr
mv debian/tmp/usr/lib/python3.8 debian/tmp/usr/lib/python3
mv: cannot stat 'debian/tmp/usr/lib/python3.8': No such file or directory
make[2]: *** [debian/rules:83: override_dh_auto_install] Error 1
make[2]: Leaving directory '/<<PKGBUILDDIR>>'
make[1]: *** [debian/rules:40: install] Error 2
make[1]: Leaving directory '/<<PKGBUILDDIR>>'
make: *** [debian/rules:40: binary] Error 2
dpkg-buildpackage: error: debian/rules binary subprocess returned exit status 2