Add support for Gnome 40

[vscsilva]

Title says it all

[nestormarius]

+1
Please add GNOME 40 support! Thank you!

[slrtbtfs]

Currently, when trying to use the extension with Gnome 40, its settings crash with the following stack trace:

Error: No property margin on GtkBox

Stack trace:
  _init/Gtk.Widget.prototype._init@resource:///org/gnome/gjs/modules/core/overrides/Gtk.js:45:40
  make_row_switch@/usr/share/gnome-shell/extensions/gamemode@christian.kellner.me/prefs.js:29:20
  _init@/usr/share/gnome-shell/extensions/gamemode@christian.kellner.me/prefs.js:19:23
  buildPrefsWidget@/usr/share/gnome-shell/extensions/gamemode@christian.kellner.me/prefs.js:111:18
  _init@resource:///org/gnome/Shell/Extensions/js/extensionsService.js:209:40
  OpenExtensionPrefsAsync/<@resource:///org/gnome/Shell/Extensions/js/extensionsService.js:122:28
  asyncCallback@resource:///org/gnome/gjs/modules/core/overrides/Gio.js:115:22
  run@resource:///org/gnome/Shell/Extensions/js/dbusService.js:177:20
  main@resource:///org/gnome/Shell/Extensions/js/main.js:19:13
  run@resource:///org/gnome/gjs/modules/script/package.js:206:19
  start@resource:///org/gnome/gjs/modules/script/package.js:190:8
  @/usr/share/gnome-shell/org.gnome.Shell.Extensions:1:17
  

[pedrofleck]

For it to work in Gnome 40, any window needs to be updated to Gtk 4.0.

[gicmo]

This should hopefully be fixed with release 5, thanks everyone for your patience.