Add dummy COMMAND to add_custom_command()
Add dummy COMMAND to add_custom_command()

Having no COMMAND at all is undocumented and breaks in CMake 2.8.0

mancoast/cado-nfs,mancoast/cado-nfs,mancoast/cado-nfs,mancoast/cado-nfs,mancoast/cado-nfs,mancoast/cado-nfs,mancoast/cado-nfs