Replace the Kitten of Death message with a warning in the banner

Replace the Kitten of Death message with a warning in the banner

 * Arguably, the Windows ports are now as (un)stable as the other
   non-Linux/x86oid ports.
 * Either way, the warning is now disabled by --noinform.
 * Also, replace the lossage message when the initial thread returns
   with a clearer description of the situation.