in_addr_t isn't available on mingw32. Just use an unsigned long instead. I
considered typedef'ing in_addr_t on mingw32 but this would potentially be
brittle if mingw32 did introduce the type.
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>