Compiling Godot on a MacOS could produce a header conflict where MacOS runtime MAX macro was used instead Core/Typedefs MAX macro
Example: Defining a FixedVector in a header file would fail, due to MacOS MAX not being a ConstEXPR
This will allow decoupling `display_server.h` from a number of headers in the
codebase which only require those enums and not all the DisplayServer API.
- Removes `native_menu.h` dependency from `display_server.h`.
It's now forward-declared in all DisplayServer implementations and should
be included in the .cpp's.
- Removes some unused `rb_set.h` and `rb_map.h` dependencies, which leads to
having to include them explicitly in half the scene and editor codebase...
which shows how much we depend on `display_server.h`.
- Forward-declare `input_event.h`, so now we need only `keyboard.h`.
Pāvels Nadtočajevs
Allen Pestaluky
Colin O'Rourke
Rémi Verschelde
Stuart Carnie
Aaron Franke