1. Do not interrupt mouse mode on virtual clicks.
2. Handle virtual clicks directly instead of sending an SDL event.
3. Fix D-Pad mouse emulation state handling.
4. Hides the modifier hints during D-Pad mouse emulation.
Introduces a `ControlDevice` global which is distinct from `ControlMode`
in that it is set to `Gamepad` even when simulating a mouse.
This allows us to avoid a number of edge cases related to mode changes.
Fixes#4242
Makes `CelSprite` unowned and adds a new `OwnedCelSprite` class for
owned sprites.
This clarifies ownership and makes the code cleaner in a number of
places.
Additionally, because the `CelSprite` class is now tiny (1 less
pointer), we can pass it by-value instead of by-reference, removing a
pointer indirection in the rendering functions.
The gamepad cursor (inventory, spells etc) no longer relies on warping a
real mouse cursor. This should make things work better on platforms that
do not support this, like Wayland.
libmpq is a much simpler alternative to StormLib for reading MPQ archives.
We use our own fork of libmpq: https://github.com/diasurgical/libmpq
Impact:
* DevilutionX is now a lot more portable. Unlike StormLib, libmpq only
needs platform-specific code for Windows.
* Locks around file access **removed** (instead we duplicate the file descriptor for streamed audio only).
* RAM usage is **300 KiB** lower than StormLib.
* Stripped release linux_x86_64 binary is **32 KiB** smaller.
* Amiga build now hangs instead of crashing.