Segfaults after removal of slice allocator

Trying to upgrade GLib 2.76.0 in NixOS, we noticed tests in several projects started to crash.

We have bisected the failure to 45b5a6c1.

We have opened issues with the projects first, in case it is wrong memory management on their part:

• GEGL: gegl#320 (closed)
• Girara: https://git.pwmt.org/pwmt/girara/-/issues/17

But with now we at three projects affected so maybe it is actually an issue with GLib. Also affected are:

• feedbackd: https://source.puri.sm/Librem5/feedbackd/-/issues/69