Fix build on recent 7.X.

Reported by:	pointyhat via kris

net/mrt/files/patch-lib::mrt::prefix.c

@@ -0,0 +1,32 @@
+Index: lib/mrt/prefix.c
+diff -u -p lib/mrt/prefix.c.orig lib/mrt/prefix.c
+--- lib/mrt/prefix.c.orig	Sat Apr 29 04:31:05 2000
++++ lib/mrt/prefix.c	Fri Jun  2 11:23:40 2006
+@@ -16,7 +16,8 @@
+ #endif /* NT */
+ 
+ 
+-#ifndef __GLIBC__
++#if !defined(__GLIBC__) && \
++    (!defined(__FreeBSD__) || !defined(HAVE_GETHOSTBYNAME_R))
+ #ifdef __osf__
+ 
+ /* apparently, OSF's gethostby{name,addr}_r's are different, broken, and
+@@ -51,7 +52,7 @@ struct hostent  *gethostbyaddr_r
+       For the time being, this part tries to convert Linux glibc 2.X
+       gethostXX_r into Solaris's that we use to code MRT. -- masaki
+     */
+-#if __GLIBC__ >= 2
++#if __GLIBC__ >= 2 || (defined(__FreeBSD__) && defined(HAVE_GETHOSTBYNAME_R))
+    /* Glibc 2.X
+ 
+     int gethostbyname_r (const char *name, struct hostent *result_buf, 
+@@ -311,7 +312,7 @@ prefix_toname (prefix_t *prefix)
+ 
+     if (prefix == NULL) return (strdup ("invalid name"));
+ 
+-#ifdef GETHOSTBYADDR_R
++#ifdef HAVE_GETHOSTBYADDR_R
+     hostinfo = gethostbyaddr_r((char *) prefix_tochar(prefix),
+ 		(prefix->bitlen)/8, prefix->family, &result,
+ 		hostbuf, sizeof hostbuf, &h_errno_r);