Add missing #includes for non-Linux systems.

diff --git a/dlls/iphlpapi/iphlpapi_main.c b/dlls/iphlpapi/iphlpapi_main.c
index d2d054e..76b1390 100644
--- a/dlls/iphlpapi/iphlpapi_main.c
+++ b/dlls/iphlpapi/iphlpapi_main.c
@@ -21,6 +21,8 @@
 #include "config.h"
 
 #include <stdlib.h>
+#include <sys/types.h>
+#include <netinet/in.h>
 #include <resolv.h>
 #include "winbase.h"
 #include "iphlpapi.h"