try borg with pypy (and cpyext) - does it work?

[ThomasWaldmann]

[ThomasWaldmann]

Tried borg with current pypy3.5 v5.9:

• borg seems to work (tried some basic commands shortly)
• tests have quite some issues: integrity errors, crashing test workers with pytest-xdist, slow msgpack, ...

[enkore]

5.8 didn't work due to some missing APIs (PyMemoryView_FromMemory).

[ThomasWaldmann]

did a quick test with pypy3.5-6.0.0 (installed on stretch64 vagrant VM via pyenv):

• llfuse does not build
• without fuse, borg builds and tests run, but quite some test failures
• uses the pure python msgpack (unclear whether this is a speed issue on pypy)

[ThomasWaldmann]

one could do a new test using pyfuse3 after #4122 is closed.