test cursors availability before exposing them

[totaam]

Issue migrated from trac ticket # 2367

component: client | priority: minor | resolution: wontfix

2019-07-25 05:48:03: antoine created the issue

---

Workaround for GTK3 under wayland: r23297

But this still causes an error, a better solution is to probe the cursors during startup and discard the ones that don't work.

[totaam]

2020-02-12 05:24:09: antoine changed status from new to assigned

[totaam]

2020-02-12 05:24:09: antoine commented

---

We may have more local cursors available since r25141.

[totaam]

2020-02-15 12:57:26: antoine changed status from assigned to closed

[totaam]

2020-02-15 12:57:26: antoine set resolution to wontfix

[totaam]

2020-02-15 12:57:26: antoine commented

---

We may have more local cursors available since r25141.
We do, but they're hard to see on win32, so r25242 updates the docstring to explain why they're still disabled on win32.

As for running under wayland, GTK still moans that it can't find the cursors.
So we don't even bother trying now: r25243.