[gtk/wip/fanc999/gtk-3-24-meson-msvc] meson: Install the icons for the demo programs

[Chun-wei Fan <fanchunwei src gnome org>]

commit 42283f1426c24047099e9a5a6056a3010a927ae7
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Tue Mar 26 17:24:03 2019 +0800

    meson: Install the icons for the demo programs
    
    Those should be installed as well, and will also eliminate the error
    that gtk-update-icon-cache failed during the post install.

 demos/gtk-demo/meson.build | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
---
diff --git a/demos/gtk-demo/meson.build b/demos/gtk-demo/meson.build
index 77992ade4e..1f8e348f6a 100644
--- a/demos/gtk-demo/meson.build
+++ b/demos/gtk-demo/meson.build
@@ -120,3 +120,17 @@ gtkapplicationdemo = executable(
   include_directories : confinc,
   install: true
 )
+
+gtk_settings_schemas = [
+  'org.gtk.Settings.FileChooser.gschema.xml',
+  'org.gtk.Settings.ColorChooser.gschema.xml',
+  'org.gtk.Settings.EmojiChooser.gschema.xml',
+  'org.gtk.Settings.Debug.gschema.xml',
+]
+
+foreach s: [ '16', '22', '24', '32', '48', '256', '512']
+  icon_destdir = join_paths(gtk_datadir, 'icons', 'hicolor', '@0@x@0@'.format(s), 'apps')
+  icons = [join_paths('data', '@0@x@0@'.format(s), 'gtk3-demo.png'),
+           join_paths('data', '@0@x@0@'.format(s), 'gtk3-demo-symbolic.symbolic.png')]
+  install_data(icons, install_dir: icon_destdir)
+endforeach