mkdir: set correct permissions on dirs created by -p

[shinhs0506]

should fix mkdir/perm.sh

1. default permission created by mkdir is a=rwx (0o0777)
2. permission of parent dirs created by -p argument is =rwx,u+wx, which is umask modified by u+wx

[github-actions]

GNU testsuite comparison:

Congrats! The gnu test tests/mkdir/perm is no longer failing!

[sylvestre]

GNU testsuite comparison:

Congrats! The gnu test tests/mkdir/perm is no longer failing!

bravo :)

[github-actions]

GNU testsuite comparison:

Congrats! The gnu test tests/mkdir/perm is no longer failing!
Congrats! The gnu test tests/tail-2/inotify-dir-recreate is no longer failing!

[cakebaker]

The two new tests (test_mkdir_parent_mode and test_mkdir_parent_mode_check_existing_parent) pass, even though I didn't apply any of the changes to mkdir.rs. Is that intentional?

[shinhs0506]

Oops, I updated the tests, they should fail now. Thanks for catching that

[github-actions]

GNU testsuite comparison:

Congrats! The gnu test tests/mkdir/perm is no longer failing!
GNU test failed: tests/tail-2/inotify-dir-recreate. tests/tail-2/inotify-dir-recreate is passing on 'main'. Maybe you have to rebase?

[github-actions]

GNU testsuite comparison:

Congrats! The gnu test tests/mkdir/perm is no longer failing!

[sylvestre]

thanks :)

[niyaznigmatullin]

I ran the test locally, and the test test_symbolic_alteration fails after this change. I think it does because my umask is 0002, which is default in my terminal, but if umask is set to 0022, then it starts working correctly. We already discussed umask issues here #3645. In my opinion, that kind of tests have to set umask explicitly before running mkdir -m, so that the tests work in every terminal window, no matter what umask is set there.