Autosave files are unsaved drawings. The autosave folder was made with
create_dir_all, by the first write or for the lock file, so on Unix it
got the default mode and other accounts on the machine could read the
files. A folder the autosaver creates is now 0o700. A folder that already
exists keeps its mode, since SAVEFILEPATH can be any folder the user
picked.
The same change as storytold/pdfcraft#3320 and storytold/vectorcraft#3406.
The accepting thread dropped failed accepts with incoming().flatten()
and asked again at once. When accepting keeps failing, for example while
the process has no file descriptors left, that loop keeps a core busy
until it recovers.
Wait 100 ms after a failed accept. The loop goes through a small helper
so the wait can be tested without running out of file descriptors.
oracola91