Implement window sharing with the hl toplevel export proto (#1179)

* implement window sharing

Co-authored-by: Mihai Fufezan <fufexan@protonmail.com>

nix/default.nix

@@ -7,6 +7,7 @@
   meson,
   ninja,
   git,
+  hyprland-protocols,
   libdrm,
   libinput,
   libxcb,
@@ -92,6 +93,10 @@ in
       # Fix hardcoded paths to /usr installation
       postPatch = ''
         sed -i "s#/usr#$out#" src/render/OpenGL.cpp
+
+        # for some reason rmdir doesn't work in a dirty tree
+        rmdir subprojects/hyprland-protocols || true
+        ln -s ${hyprland-protocols} subprojects/hyprland-protocols
       '';
 
       passthru.providedSessions = ["hyprland"];