This also adds the ability to query how many virtual desktops are
set up, and for the Taskbar to be notified when the active virtual
desktop has changed.
This allows WindowServer to use multiple framebuffer devices and
compose the desktop with any arbitrary layout. Currently, it is assumed
that it is configured contiguous and non-overlapping, but this should
eventually be enforced.
To make rendering efficient, each window now also tracks on which
screens it needs to be rendered. This way we don't have to iterate all
the windows for each screen but instead use the same rendering loop and
then only render to the screen (or screens) that the window actually
uses.
This changes client methods so that they return the IPC response's
return value directly - instead of the response struct - for IPC
methods which only have a single return value.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
