new: x11/xapp-symbolic-icons

One of the responses to Gnome Project making the Adwaita icon themes 
'private' in May 2024 is an icon set used by 'Xapps applications', used 
primarily by the Cinnamon DE/Linux Mint.

xapp-symbolic-icons is a collection of fallback symbolic icons installed 
under the x11/hicolor-icon-theme base directory. The icon names are 
prefixed with 'xapp-' and a Python3 utility is provided to 'convert' 
source code to use them.

This port is based on xapp-symbolic-icons as a low-friction response to 
the deprecation of the Adwaita icon themes for non- 'Gnome Core 
Applications' [1]

The xapp- prefix is stripped from the icon names and the Python utility 
removed.

With the port installed, non-Gnome-Core GTK (and other) applications 
using symbolic action icons will use a compatible fallback icon when 
Adwaita or other icon themes are not installed or configured on 
non-Gnome DE/WMs.

Otherwise, there is a fair chance some icons will be missing. You could 
say it aims at 'sane defaults'.

This port complements the x11/adwaita-xfce-icon-theme I proposed to the 
list recently. Tweaked version also attached- adds some xfce-specific 
symbolic icons, allows selection in Xfce 'Appearance' GUI, and requires 
configuring 'adwaita-xfce' as the active theme in other environments.

Tested on 7.9-stable/-current with Xfce and dwm tiling WM.

Advice please: since the port is only 'based on' xapp-symbolic-icons, 
would a better PKGNAME be something like 'hicolor-symbolic-icons-extra'?

Chris

[1] https://marc.info/?l=openbsd-ports&m=178703593543096&w=2