NetBSD master CVS tree commits

[source%NetBSD.ORG@localhost]

phil
Mon Jul  7 13:57:48 PDT 1997
Update of /cvsroot/src/sys/netinet
In directory netbsd1:/var/slash-tmp/cvs-serv11783

Modified Files:
        in_systm.h 
Log Message:
Protect against double inclusion.  PR 3524.