prevent infinite loop if gtk_menu_popup() fails, fixes #15387

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@74624 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Signed-off-by: Marian 'VooDooMan' Meravy <vdm113@gmail.com>

Conflicts:
	src/gtk/window.cpp