added some minor protection against multiple inclusion

diff --git a/netdissect-stdinc.h b/netdissect-stdinc.h
index e201afa45a317a2826138ccca281eaab9fa4f88e..c7070f0a04c25453fc7aba7e50da66c4d1aa1401 100755 (executable)
--- a/netdissect-stdinc.h
+++ b/netdissect-stdinc.h
@@ -319,6 +319,7 @@ typedef char* caddr_t;
  * define struct in6_addr so that we can use it for IPv6 addresses.
  */
 #ifndef HAVE_OS_IPV6_SUPPORT
+#ifndef AF_INET6
 #define AF_INET6       24
 
 struct in6_addr {
@@ -329,11 +330,12 @@ struct in6_addr {
        } __u6_addr;                    /* 128-bit IP6 address */
 };
 #endif
+#endif
 
 #ifndef NI_MAXHOST
 #define        NI_MAXHOST      1025
 #endif
-  
+
 #ifndef INET_ADDRSTRLEN
 #define INET_ADDRSTRLEN 16
 #endif