Without this, kitty fails to compile:
```
glfw/cocoa_init.m:462:14: error: case value not in enumerated type
'NSEventModifierFlags' (aka 'enum NSEventModifierFlags')
[-Werror,-Wswitch]
case (NSEventModifierFlagShift | NSEventModifierFlagOption):
^
glfw/cocoa_init.m:465:14: error: case value not in enumerated type
'NSEventModifierFlags' (aka 'enum NSEventModifierFlags')
[-Werror,-Wswitch]
case (NSEventModifierFlagShift | NSEventModifierFlagCommand):
^
```
I thought about changing the type of the `modifierFlags` function parameter from `NSEventModifierFlags` to `NSUInteger` since `NSEventModifierFlags` is defined as an enum according to https://developer.apple.com/documentation/appkit/nseventmodifierflags?language=objc and is technically not the proper type for a bit field. But since Apple themselves define `modifierFlags` as `NSEventModifierFlags` according to https://developer.apple.com/documentation/appkit/nsevent/1534405-modifierflags?language=objc, I think the fix in this commit is better.
This warning was introduced with commit f9944e614088c4977ad9c9f1d1b44d97643e8d5b.
This piece of code is not run when the `GLFW_COCOA_MENUBAR` init hint is set to `0`, which kitty does.
This reduces the difference to GLFW upstream a little.
GLFW creates the menu bar in the applicationWillFinishLaunching method, while kitty creates it in `create_os_window()`. This patch changes the behaviour to match GLFW.
In practice, without this change, there can be a short time where the menu bar is not fully populated.
The time is stored in a signed 64 bit integer with nanosecond accuracy. This eliminates the possibility of floating-point inaccuracies.
`monotonic_t` can currently hold values large enough to work correctly for more than 200 years into the future.
Using a typedef instead of directly using `int64_t` everywhere will also allow easily changing the datatype in the future should the need arise for more precise or bigger time values.
Also reduce input latency by ignoring repaint_delay when
there is actual pending input.
Gets rid of request_tick_callback(). Now empty events
result in the tick callback being called so there is only a
single mechanism for waking up the main loop and getting
the tick callback called.
