[gtk] Adwaita: Add color defines from 3.24

[Timm Bäder <baedert src gnome org>]

commit 2dfb8de0ec93dfbb84df59841d8a43ff3c1cbb7f
Author: frederik.feichtmeier <frederik feichtmeier gmail com>
Date:   Fri Jul 26 08:10:15 2019 -0400

    Adwaita: Add color defines from 3.24

 gtk/theme/Adwaita/_colors.scss | 8 ++++++++
 1 file changed, 8 insertions(+)
---
diff --git a/gtk/theme/Adwaita/_colors.scss b/gtk/theme/Adwaita/_colors.scss
index a39ac7b6f6..810a668539 100644
--- a/gtk/theme/Adwaita/_colors.scss
+++ b/gtk/theme/Adwaita/_colors.scss
@@ -67,3 +67,11 @@ $backdrop_scrollbar_bg_color: darken($backdrop_bg_color, 3%);
 $backdrop_scrollbar_slider_color: mix($backdrop_fg_color, $backdrop_bg_color, 40%);
 
 $backdrop_menu_color: if($variant == 'light', $backdrop_base_color, mix($backdrop_bg_color, 
$backdrop_base_color, 20%));
+
+//special cased widget colors
+$suggested_bg_color: $selected_bg_color;
+$suggested_border_color: $selected_borders_color;
+$progress_bg_color: $selected_bg_color;
+$progress_border_color: $selected_borders_color;
+$checkradio_bg_color: $selected_bg_color;
+$checkradio_fg_color: $selected_fg_color;