[glib] (6 commits) Non-fast-forward update to branch wip/pwithnall/macos-werror

[Philip Withnall <pwithnall src gnome org>]

The branch 'wip/pwithnall/macos-werror' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  345bafa... gutils: Disable some dead code on macOS
  72f9f19... ci: Enable --werror on macOS

Commits added to the branch:

  bc04b57... gtypes: Rework checked arithmetic handling (*)
  b5dade1... Get back to '-werror' with warnings at level 3 (*)
  30c3f05... Merge branch 'back_to_werror' into 'main' (*)
  81a31fd... Merge branch '2523-checked-arithmetic' into 'main' (*)
  6554af0... gutils: Disable some dead code on macOS
  8d54617... ci: Enable --werror on macOS

(*) This commit already existed in another branch; no separate mail sent