Bug#1077757: gtk4: Failing autopkgtest on s390x

[Jeremy Bícha]

Source: gtk4
Version: 4.14.4+ds-7
Severity: serious

gtk4's autopkgtest is failing on s390x. This is preventing gtk4 from
being eligible for migration to Testing.

https://ci.debian.net/packages/g/gtk4/testing/s390x/

autopkgtest log excerpt
--------------------------------
# Running test: gtk-4.0/gdk/memorytexture.test
# FAIL: gtk-4.0/gdk/memorytexture.test (Child process exited with code 134)
not ok - gtk-4.0/gdk/memorytexture.test
…
# SUMMARY: total=88; passed=87; skipped=0; failed=1; user=21.5s;
system=2.7s; maxrss=345184
# FAIL: gtk-4.0/gdk/memorytexture.test (Child process exited with code 134)
autopkgtest [12:10:15]: test installed-tests-x11: -----------------------]
autopkgtest [12:10:15]: test installed-tests-x11:  - - - - - - - - - -
results - - - - - - - - - -
installed-tests-x11  FAIL non-zero exit status 2

other info
-------------
There were several upstream fixes to the memorytexture test in June
and July that aren't in our gtk 4.14.4

https://gitlab.gnome.org/GNOME/gtk/-/commits/main/testsuite/gdk/memorytexture.c

We do have a patch,
debian/tests-Mark-memorytexture-as-expected-to-fail-on-big-endian.patch

I'm unsure about the significance: did this test actually pass on
s390x in 4.12 and then began failing again in 4.14?

gdk/memorytexture.test passes in installed-tests-wayland but not in
installed-tests-x11

Thank you,
Jeremy Bícha