[gtk+] (8 commits) Non-fast-forward update to branch wip/cosimoc/viewport-gadget

[Cosimo Cecchi <cosimoc src gnome org>]

The branch 'wip/cosimoc/viewport-gadget' 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:

  0e2c1ea... viewport: use gtk_container_class_handle_border_width()
  b2db963... viewport: trivial code cleanup
  c74748d... viewport: port to use a gadget

Commits added to the branch:

  d0d8671... Forgotten files (*)
  c0bc0a9... gtkcssnumbervalue.c: Include fallback-c89.c to fix build (*)
  e20826f... label: Deny drag gesture when not selectable (*)
  08f928a... Adwata: fix switch slider border clash (*)
  157276b... Adwaita: use min-height/width for entry and button sizing (*)
  6239d65... viewport: use gtk_container_class_handle_border_width() (*)
  1c44a33... viewport: trivial code cleanup (*)
  cb07104... viewport: port to use a gadget (*)

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