qemu_next_alarm_deadline() is needed by MinGW, too.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>
Acked-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NStefan Weil <weil@mail.berlios.de>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>