On some systems (NetBSD 1.6 and Solaris 9, at least), GCC doesn't understand

the semantics of assert(0) and believes it can return.  Add a gratuitous
exit(1) to convince it that this won't happen, and hence quell a couple of
warnings about variables' being used uninitialised.

[originally from svn r5669]

unix/uxnet.c

@@ -576,6 +576,7 @@ static int try_connect(Actual_Socket sock)
 
       default:
 	assert(0 && "unknown address family");
+	exit(1); /* XXX: GCC doesn't understand assert() on some systems. */
     }
 
     fl = fcntl(s, F_GETFL);