It is not uncommon for clients to redundantly set the window size and position, either as a holdover from an SDL 1 port, when this was required, due to any window state change triggering a universal update function that sets all window state, even if unnecessary (e.g. always calling SDL_SetWindowSize(), even if the window is fullscreen), or due to the use of compatability layers. Historically, these clients expect that their behavior won't override the base window state, which is an assumption that the windowing changes in SDL 3 broke by caching size and position changes that can't be applied immediately.
This change drops size and position requests when the window is in the maximized and fullscreen states (fullscreen-desktop windows will be repositioned, but the non-fullscreen floating position will not be overwritten), which is behavior more in line with existing client assumptions, and should ease the porting process, as well as prevent annoying bugs when older software is run via sdl2-compat.
In the process of making these changes, pending window state has been moved to separate variables in the SDL_Window struct, as this fixes bugs regarding fullscreen display selection and centering windows immediately after resize on asynchronous platforms, which had issues due to pending state possibly being overwritten.
I'm going to reuse that code for an actual drag/drop example later, but for
simplicity and accessibility of the examples, this is just going to load two
wavs and loop them, so you get the music with a sword-clinking sound mixed
over it.
Standard I/O doesn't work well with non-blocking handles, so make sure any pipes are in blocking mode before launching child processes.
Fixes https://github.com/libsdl-org/SDL/issues/10998
X11 seems to need a slight delay before warping the pointer to ensure that the window is actually fully visible on the desktop, or the pointer enter event may not be sent.
This also disables the warp focus test on XWayland, as warping the mouse cursor when outside the window on any Wayland desktop usually just doesn't work.
SDL_DelayNS() now passes through to the high precision OS delay function, and SDL_DelayPrecise() tries to busy wait to get as close as possible to the desired wait time.
Fixes https://github.com/libsdl-org/SDL/issues/11141
