configure: add missing INCLUDE to netnsid detection

Fixes: d116ff34145b0 ("ip netns: Fix rtnl error while print netns list")
Signed-off-by: Jiri Benc <jbenc@redhat.com>
diff --git a/configure b/configure
index 631938e..e54f4b6 100755
--- a/configure
+++ b/configure
@@ -224,7 +224,7 @@
 #include <linux/rtnetlink.h>
 int test_def = RTM_GETNSID;
 EOF
-    $CC -c $TMPDIR/netnsid.c >/dev/null 2>&1
+    $CC -I$INCLUDE -c $TMPDIR/netnsid.c >/dev/null 2>&1
     if [ $? -eq 0 ]
     then
 	echo "IP_CONFIG_NETNSID:=y" >> Config