Crash on iOS

[naithar]

Bevy version
5df6804

Operating system & version
iOS 14.0.1

What happened
Running any iOS bevy app results in crash on startup.

Additional information

Commenting out this lines fixes the issue:

bevy/crates/bevy_winit/src/winit_windows.rs

Lines 74 to 77 in d004bce

	winit_window
	.set_cursor_grab(window.cursor_locked())
	.unwrap();
	winit_window.set_cursor_visible(window.cursor_visible());

Seems like #679 introduced this crash.

Logs:

2020-10-18 02:01:26.418233+0300 BevyTest[12738:4248545] fopen failed for data file: errno = 2 (No such file or directory)
2020-10-18 02:01:26.418290+0300 BevyTest[12738:4248545] Errors found! Invalidating cache...
thread '<unnamed>' panicked at 'called `Result::unwrap()` on an `Err` value: NotSupported(NotSupportedError)', bevy/crates/bevy_winit/src/winit_windows.rs:76:14
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
fatal runtime error: failed to initiate panic, error 5

[cart]

Resolved by #703