treewide: Implement ext-foreign-toplevel-info
See wlroots MR
https://gitlab.freedesktop.org/wlroots/wlroots/-/merge_requests/4543
Test client: https://git.sr.ht/~leon_plickat/lswt
./lswt --force-protocol ext-foreign-toplevel-list-v1
With the toplevel handle code cleaned up in !626 (merged) adding this new protocol is straight forward. I've folded up some cleanups from the wlroots-0.19.x branch to make that diff smaller.
/cc @arun-mani-j please have a look
Edited by Guido Günther