Don't run code in the signal handler, only set a flag.
Use sigaction(2) to avoid non-portable signal(2) semantics.
Make #ifdefs less messy.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-id: 1385130903-20531-1-git-send-email-kraxel@redhat.com
Signed-off-by: Anthony Liguori <aliguori@amazon.com>