bpo-38811: Check for presence of os.link method in pathlib (GH-17225)


Commit 6b5b013bcc22 ("bpo-26978: Implement pathlib.Path.link_to (Using
os.link) (GH-12990)") introduced a new link_to method in pathlib. However,
this makes pathlib crash when the 'os' module is missing a 'link' method.

Fix this by checking for the presence of the 'link' method on pathlib
module import, and if it's not present, turn it into a runtime error like
those emitted when there is no lchmod() or symlink().

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
(cherry picked from commit 092435e932dee1802784ec28f39454f50fdd879a)

Co-authored-by: Toke Høiland-Jørgensen <toke@redhat.com>
3 files changed