reftest_compare_surfaces: Report how much the images differ

In unattended/non-interactive/autobuilder environments where the images
are not trivially accessible, this provides a way to distinguish between
totally different rendering and more subtle issues.

Signed-off-by: Simon McVittie <smcv@debian.org>
Forwarded: https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/3195
Applied-upstream: no, upstream want reftests to be a strict pass/fail with identical results required

Gbp-Pq: Name reftest_compare_surfaces-Report-how-much-the-images-diffe.patch

egl: Fix invalid format string

(cherry picked from commit 4f2b1b3cfcf1f11f14993656c21105bbbb9432d7)

Gbp-Pq: Name egl-Fix-invalid-format-string.patch

gtk4 (4.6.4+ds-3+rpi1) bookworm-staging; urgency=medium

  [changes brought forward from 4.4.0+ds1-5+rpi1 by Peter Michael Green <plugwash@raspbian.org> at Tue, 07 Sep 2021 10:26:09 +0000]
  * Disable a couple of faliing tests in Raspbian.
  * Fix clean target.

[dgit import unpatched gtk4 4.6.4+ds-3+rpi1]

Import gtk4_4.6.4+ds-3+rpi1.debian.tar.xz

[dgit import tarball gtk4 4.6.4+ds-3+rpi1 gtk4_4.6.4+ds-3+rpi1.debian.tar.xz]

Import gtk4_4.6.4+ds.orig.tar.xz

[dgit import orig gtk4_4.6.4+ds.orig.tar.xz]