Make sure mouse cursor is not left disabled when exiting

[th-otto]

No description provided.

[hifi]

Shouldn't this be enabled for all platforms?

[th-otto]

Maybe, yes. At least it should not hurt (theoretically). But i could test it only on linux, and there it does not seem do be needed. Reason why it may be needed on other platforms is for example

Vanilla-Conquer/common/wwkeyboard.cpp

Lines 550 to 551 in e57652a

	case SDL_QUIT:
	exit(0);

[OmniBlade]

This the cause of #836