To avoid a mismatch between the state of pressed keys as held by the
hotkey thread and keys pressed while the application is in focus, local
key events need to be monitored as well (even though they are already
handled by Cocoa's main event loop).
Also remove use of deprecated [NSProcessInfo operatingSystem]. It always
returns the NSMACHOperatingSystem.
Also stop parsing [NSProcessInfo operatingSystemVersionString]. The
documentation explicitly says "not for parsing".
On 10.15, if a user activates secure input of some sort, the hotkey code
will begin to crash inside of any Apple function related to hotkeys,
even after secure input has ended. This does not appear to be the fault
of OBS; the reason to this is still as of yet unknown, but is suspected
to be a bug inside of Apple code that's a new regression as of 10.15.
So for the time being as a temporary solution to the crash, simply
disable external hotkey support once secure input has been detected.
Because of this issue, the hotkey code should probably be replaced by a
different method of tracking hotkeys, perhaps InstallEventHandler for
example. This commit is little more than a bandaid to the crash.
