Commit 3dbf5038fab8eb0d8c11 tried to defer focus changes
until after rendering is done. But it failed to do so, since
the toplevel ::render handler is still before rendering of
popups that are attached to that toplevel. To do this
properly, we need to do it in the AFTER_PAINT frame clock
phase.

Fixes: #3725

scrolledwindow: Stop using scroll cursors

See merge request GNOME/gtk!3416

ci: Drop the split Fedora images

See merge request GNOME/gtk!3415

We used to override cursor to use all-scroll while the
content is being scrolled. Unfortunately, there is several
problems with this:
- It is really only expected certain devices, and we don't
  have the device information on Wayland
- With the way cursor setting works in GTK4, non-NULL cursors
  of the content (eg the text views ibeam) win, making the
  scroll cursor not show up
- Under X11, we seem to miss scroll end events and then
  the scroll cursor gets stuck
Therefore, just remove this feature.

Now that we don't need the whole of Pandoc to build our documentation,
we can go back to a single Fedora image for our CI.

ngl: Use fp16 for colors

See merge request GNOME/gtk!3405

wayland: Improve font setting fallback more

Closes #3838

See merge request GNOME/gtk!3412

alias attributes don't work on Darwin, so
do without.

Use an IFUNC resolver to determine whether we can use
intrinsics for FP16 conversion. This requires the functions
to be no longer inline.

Sadly, it turns out that __builtin_cpu_supports ("f16c")
doesn't compile on the systems where we want it to prevent
us from getting a SIGILL at runtime.

And add a compile time check for the presence of this
CPU feature.