check for struct sizes and use those sizes if the NS_* defines are lacking

(IRIX 6.5.22 it seems)

ares/configure.ac

@@ -188,4 +188,38 @@ int main()
      ], AC_MSG_RESULT(no),AC_MSG_RESULT(no))
 fi
 
+AC_CHECK_SIZEOF(struct in6_addr, ,
+[
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#ifdef HAVE_WINSOCK_H
+#include <winsock.h>
+#endif
+#ifdef HAVE_NETINET_IN_H
+#include <netinet/in.h>
+#endif
+]
+)
+AC_CHECK_SIZEOF(struct in_addr, ,
+[
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#ifdef HAVE_WINSOCK_H
+#include <winsock.h>
+#endif
+#ifdef HAVE_NETINET_IN_H
+#include <netinet/in.h>
+#endif
+]
+)
+
+
 AC_OUTPUT(Makefile)

ares/inet_net_pton.h

@@ -39,4 +39,16 @@ int ares_inet_pton(int af, const char *src, void *dst);
 int ares_inet_net_pton(int af, const char *src, void *dst, size_t size);
 #endif
 
+#ifndef NS_IN6ADDRSZ
+#define NS_IN6ADDRSZ SIZEOF_STRUCT_IN6_ADDR
+#endif
+
+#ifndef NS_INADDRSZ
+#define NS_INADDRSZ SIZEOF_STRUCT_IN_ADDR
+#endif
+
+#ifndef NS_INT16SZ
+#define NS_INT16SZ 2
+#endif
+
 #endif /* INET_NET_PTON_H */