bcc: 0.26.0 -> 0.28.0 (#240520)
* bcc: 0.26.0 -> 0.28.0
update now calls setuptool through cmake which installs an egg file,
this apparently requires setting a PYTHONPATH which includes the
output dir to work.
While here, make it clear we only support python3 as 'python' in
nixpkgs is still python2 even if it's no longer usable...
* bcc/bpftrace: use llvm 16
authored by Dominique Martinet and committed by GitHub 184dfbc8 87dfa279