+if test "x$have_ip6_ext" = "xno"; then
+ SAVE_CFLAGS="$CFLAGS"
+ CFLAGS="$CFLAGS -DSOLARIS2=8"
+
+ AC_CHECK_TYPES([struct ip6_ext],
+ [have_ip6_ext="yes, with -DSOLARIS2=8"],
+ [have_ip6_ext="no"],
+[#if HAVE_STDINT_H
+# include <stdint.h>
+#endif
+#if HAVE_SYS_TYPES_H
+# include <sys/types.h>
+#endif
+#if HAVE_NETINET_IN_SYSTM_H
+# include <netinet/in_systm.h>
+#endif
+#if HAVE_NETINET_IN_H
+# include <netinet/in.h>
+#endif
+#if HAVE_NETINET_IP6_H
+# include <netinet/ip6.h>
+#endif
+])
+
+ if test "x$have_ip6_ext" = "xno"; then
+ CFLAGS="$SAVE_CFLAGS"
+ fi
+fi
+