Caused by upgrade to 'next' (python 3.9).

Dependency for borgbackup (currently at 1.2.2)

build log and environment log attached.

epro show
=== Enabled Profiles: ===
arch: x86-64bit
build: next
subarch: intel64-sandybridge
flavor: desktop
mix-ins: gfxcard-nvidia
=== Python kit: ===
branch: next
=== All inherited flavor from desktop flavor: ===
workstation (from desktop flavor)
core (from workstation flavor)
minimal (from core flavor)
=== All inherited mix-ins from desktop flavor: ===
X (from workstation flavor)
audio (from workstation flavor)
dvd (from workstation flavor)
media (from workstation flavor)
mediadevice-audio-consumer (from media mix-in)
mediadevice-base (from mediadevice-audio-consumer mix-in)
mediadevice-video-consumer (from media mix-in)
mediadevice-base (from mediadevice-video-consumer mix-in)
mediaformat-audio-common (from media mix-in)
mediaformat-gfx-common (from media mix-in)
mediaformat-video-common (from media mix-in)
console-extras (from workstation flavor)
print (from desktop flavor)
=== All inherited mix-ins from gfxcard-nvidia mix-ins: ===
core-gl-kit:gfxcard-nvidia (from gfxcard-nvidia mix-in)