Add support for the wl_pointer.warp event from Wayland protocol version 11.
https://gitlab.freedesktop.org/wayland/wayland/-/merge_requests/340
This allows the compositor to notify clients when the pointer position has
changed due to surface movement or compositor action, rather than input device
motion. This is useful for tracking cursor position across surface boundaries
and dynamic repositioning.
Stop trying to maintain a per-file _POSIX_C_SOURCE. Instead,
require POSIX.1-2008 globally. A lot of core source files depend
on that already.
Some care must be taken on a few select files where we need a bit
more than POSIX. Some files need XSI extensions (_XOPEN_SOURCE) and
some files need BSD extensions (_DEFAULT_SOURCE). In both cases,
these feature test macros imply _POSIX_C_SOURCE. Make sure to not
define both these macros and _POSIX_C_SOURCE explicitly to avoid
POSIX requirement conflicts (e.g. _POSIX_C_SOURCE says POSIX.1-2001
but _XOPEN_SOURCE says POSIX.1-2008).
Additionally, there is one special case in render/vulkan/vulkan.c.
That file needs major()/minor(), and these are system-specific.
On FreeBSD, _POSIX_C_SOURCE hides system-specific symbols so we need
to make sure it's not defined for this file. On Linux, we can
explicitly include <sys/sysmacros.h> and ensure that apart from
symbols defined there the file only uses POSIX toys.
When integrating wlroots with another toolkit, wlroots may receive
wl_pointer.enter events for surfaces not backed by a wlr_output.
Ignore such surfaces by tagging the ones we're aware of with
wl_proxy_set_tag().
Currently, the "wlr_event_pointer_axis" event stores low-resolution
values in its "delta_discrete" field. Low-resolution values are always
multiples of one, i.e., 1 for one wheel detent, 2 for two wheel
detents, etc.
In order to simplify internal handling of events, always transform in
the backend from the low-resolution value into the high-resolution
value.
The transformation is performed by multiplying by 120. The 120 magic
number is used by the kernel and it is exposed to clients in the
"WLR_POINTER_AXIS_DISCRETE_STEP" constant.
All the code logic related to the pointer has been moved to its own file.
The seat is responsible for the lifetime of its wlr_wl_pointer(s), and assigning
them to the relevant wlr_wl_output. The wlr_wl_pointer becomes a simple helper
to manager the wlr_pointer associated to the seat's wl_pointer and its lifetime.
