Deprecation warnings when generating Adwaita css files
[1/1274] Generating Adwaita theme variant: dark with a custom command.
DEPRECATION WARNING on line 183 of /home/baedert/Source/gnome/gtk+/gtk/theme/Adwaita/_drawing.scss:
!global assignments won't be able to declare new variables in future versions.
Consider adding `$button-fill: null` at the top level.
[2/1274] Generating Adwaita theme with a custom command.
DEPRECATION WARNING on line 183 of /home/baedert/Source/gnome/gtk+/gtk/theme/Adwaita/_drawing.scss:
!global assignments won't be able to declare new variables in future versions.
Consider adding `$button-fill: null` at the top level.
[3/1274] Generating HighContrast theme variant: inverse with a custom command.
DEPRECATION WARNING on line 183 of /home/baedert/Source/gnome/gtk+/gtk/theme/Adwaita/_drawing.scss:
!global assignments won't be able to declare new variables in future versions.
Consider adding `$button-fill: null` at the top level.
[4/1274] Generating HighContrast theme with a custom command.
DEPRECATION WARNING on line 183 of /home/baedert/Source/gnome/gtk+/gtk/theme/Adwaita/_drawing.scss:
!global assignments won't be able to declare new variables in future versions.
Consider adding `$button-fill: null` at the top level.