configure: add test for whether required IPv6 helpers

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/configure b/configure
index 2dda142..6baa579 100755
--- a/configure
+++ b/configure
@@ -1091,6 +1091,31 @@
 fi
 echo "pwritev/preadv                $pwritev"
 
+##########################################
+# Check whether we have the required functions for ipv6
+ipv6="no"
+cat > $TMPC << EOF
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <stdio.h>
+int main(int argc, char **argv)
+{
+  struct addrinfo hints;
+  struct in6_addr addr;
+  int ret;
+
+  ret = getaddrinfo(NULL, NULL, &hints, NULL);
+  freeaddrinfo(NULL);
+  printf("%s\n", gai_strerror(ret));
+  addr = in6addr_any;
+  return 0;
+}
+EOF
+if compile_prog "" "" "ipv6"; then
+  ipv6="yes"
+fi
+echo "IPv6 helpers                  $ipv6"
 
 #############################################################################
 
@@ -1210,6 +1235,9 @@
 if test "$pwritev" = "yes" ; then
   output_sym "CONFIG_PWRITEV"
 fi
+if test "$ipv6" = "yes" ; then
+  output_sym "CONFIG_IPV6"
+fi
 
 echo "LIBS+=$LIBS" >> $config_host_mak
 echo "CFLAGS+=$CFLAGS" >> $config_host_mak