Mk/bsd.port.mk: Setting XDG_DATA_HOME=${STAGEDIR}${PREFIX}/share instead of XDG_DATA_HOME=${WRKDIR} which was wrong

[yuri]

Summary

xdg-utils use XDG_DATA_HOME as a destination of desktop-related files, like .desktop, icons, etc.

See the port here as an example: https://bugs.freebsd.org/bugzilla/attachment.cgi?id=188569&action=diff It has to move icons, etc from WRKDIR.

[mat]

Some software use XDG_DATA_HOME to write stuff during the build, so it cannot be pointed to anything else than than the only place where one is allowed to write during the build, which is WRKDIR.

If one port breaks because of this, it is not the framework's fault, please fix that port.

[yuri]

Ok!