add_feature_info for screen sharing window selection

CMakeLists.txt

@@ -449,8 +449,13 @@ endif()
 include(FindPkgConfig)
 pkg_check_modules(GSTREAMER IMPORTED_TARGET gstreamer-sdp-1.0>=1.18 gstreamer-webrtc-1.0>=1.18)
 if (TARGET PkgConfig::GSTREAMER)
-	pkg_check_modules(XCB IMPORTED_TARGET xcb xcb-ewmh)
 	add_feature_info(voip ON "GStreamer found. Call support is enabled automatically.")
+	pkg_check_modules(XCB IMPORTED_TARGET xcb xcb-ewmh)
+	if (TARGET PkgConfig::XCB)
+		add_feature_info("Window selection when screen sharing (X11)" ON "XCB-EWMH found. Window selection is enabled when screen sharing (X11).")
+	else()
+		add_feature_info("Window selection when screen sharing (X11)" OFF "XCB-EWMH could not be found on your system.  Screen sharing (X11) is limited to the entire screen only. To enable window selection, make sure xcb and xcb-ewmh can be found via pkgconfig.")
+	endif()
 else()
 	add_feature_info(voip OFF "GStreamer could not be found on your system.  As a consequence call support has been disabled. If you don't want that, make sure gstreamer-sdp-1.0>=1.18 gstreamer-webrtc-1.0>=1.18 can be found via pkgconfig.")
 endif()