diff -urN bind-8.3.0-T1A/src/port/cygwin/bin/probe_ipv6 bind-8.3.0-T1A-cygwin/src/port/cygwin/bin/probe_ipv6
--- bind-8.3.0-T1A/src/port/cygwin/bin/probe_ipv6	Wed Dec 31 16:00:00 1969
+++ bind-8.3.0-T1A-cygwin/src/port/cygwin/bin/probe_ipv6	Wed Jul 25 02:13:30 2001
@@ -0,0 +1,55 @@
+#!/bin/sh
+
+set -e
+PATH=/bin:/usr/bin:$PATH; export PATH
+trap "rm -f tmp$$a.c tmp$$b.c tmp$$a.o tmp$$b.o" 0
+target=port_ipv6
+new=new_${target}.h
+old=${target}.h
+
+cat > tmp$$a.c <<EOF
+#include <sys/types.h>
+#include <netinet/in.h>
+struct sockaddr_in6 xx;
+EOF
+
+cat > tmp$$b.c <<EOF
+#include <sys/types.h>
+#include <netinet/in.h>
+struct in6_addr xx;
+EOF
+
+cat > ${new} <<EOF
+
+/* This file is automatically generated. Do Not Edit. */
+
+#ifndef ${target}_h
+#define ${target}_h
+
+EOF
+
+if ${CC} -c tmp$$a.c > /dev/null 2>&1
+then
+        echo "#define HAS_INET6_STRUCTS" >> ${new}
+        if ${CC} -c tmp$$b.c > /dev/null 2>&1
+        then
+		:
+	else
+                echo "#define in6_addr in_addr6" >> ${new}
+        fi
+else
+        echo "#undef HAS_INET6_STRUCTS" >> ${new}
+fi
+echo  >> ${new}
+echo "#endif" >> ${new}
+if [ -f ${old} ]; then
+        if cmp -s ${new} ${old} ; then
+                rm -f ${new}
+        else
+                rm -f ${old}
+                mv ${new} ${old}
+        fi
+else
+        mv ${new} ${old}
+fi
+exit 0
diff -urN bind-8.3.0-T1A/src/port/cygwin/include/Makefile bind-8.3.0-T1A-cygwin/src/port/cygwin/include/Makefile
--- bind-8.3.0-T1A/src/port/cygwin/include/Makefile	Tue Nov 21 04:54:57 2000
+++ bind-8.3.0-T1A-cygwin/src/port/cygwin/include/Makefile	Wed Jul 25 02:19:52 2001
@@ -65,10 +65,15 @@
 		(cd $$x; pwd; ${MAKE} ${MARGS} $@) || exit 1; \
 	done
 
+all depend:: port_ipv6.h
+
+port_ipv6.h: FRC
+	probe_ipv6
+
 distclean:: clean
 
 clean::
-	rm -f *~ *.BAK *.CKP *.orig
+	rm -f *~ *.BAK *.CKP *.orig port_ipv6.h
 
 links: FRC
 	@set -e; ln -s SRC/*.h .
diff -urN bind-8.3.0-T1A/src/port/cygwin/include/port_after.h bind-8.3.0-T1A-cygwin/src/port/cygwin/include/port_after.h
--- bind-8.3.0-T1A/src/port/cygwin/include/port_after.h	Wed Jun 20 20:52:30 2001
+++ bind-8.3.0-T1A-cygwin/src/port/cygwin/include/port_after.h	Wed Jul 25 02:17:42 2001
@@ -9,8 +9,8 @@
 #define HAVE_MINIMUM_IFREQ
 #define HAVE_CHROOT
 #define CAN_CHANGE_ID
-#define HAS_INET6_STRUCTS 
-#define MISSING_IN6ADDR_ANY
+#define NEED_IN6ADDR_ANY
+#define NEED_SOCKADDR_STORAGE
 #define SPRINTF_INT
 #define VSPRINTF_INT
 #define __BIND_RES_TEXT
@@ -57,6 +57,8 @@
 /* SunOS provides vsprintf but doesn't prototype it. */
 #include <stdarg.h>
 
+#include <port_ipv6.h>
+
 /*
  * We need to know the IPv6 address family number even on IPv4-only systems.
  * Note that this is NOT a protocol constant, and that if the system has its
@@ -93,14 +95,17 @@
 	struct in6_addr	sin6_addr;	/* IPv6 address */
 	u_int32_t	sin6_scope_id;	/* set of interfaces for a scope */
 };
+#endif /* HAS_INET6_STRUCTS */
 
+/* for Cygwin up to now (!) need to define these in the 'net includes 
+   if HAS_INET6_STRUCTS can be defined! */
 #ifndef IN6ADDR_ANY_INIT
 #define	IN6ADDR_ANY_INIT	{{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}}
 #endif
+
 #ifndef IN6ADDR_LOOPBACK_INIT
 #define	IN6ADDR_LOOPBACK_INIT	{{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1}}
 #endif
-#endif  /* HAS_INET6_STRUCTS */
 
 #if defined(NEED_SOCKADDR_STORAGE) || !defined(HAS_INET6_STRUCTS)
 #define __SS_MAXSIZE 128
diff -urN bind-8.3.0-T1A/src/port/cygwin/include/sys/un.h bind-8.3.0-T1A-cygwin/src/port/cygwin/include/sys/un.h
--- bind-8.3.0-T1A/src/port/cygwin/include/sys/un.h	Sun Apr  1 11:11:49 2001
+++ bind-8.3.0-T1A-cygwin/src/port/cygwin/include/sys/un.h	Wed Jul 25 01:56:20 2001
@@ -0,0 +1,6 @@
+#ifndef _cygwin_sys_un_h
+#define _cygwin_sys_un_h
+
+#include_next <sys/un.h>
+
+#endif