diff --git a/configure.ac b/configure.ac
index 11772444ee..d9b7a247e0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3035,6 +3035,7 @@ AC_CHECK_FUNCS([fork \
   getpwuid \
   getrlimit \
   gettimeofday \
+  if_nametoindex \
   inet_addr \
   perror \
   pipe \
diff --git a/lib/url.c b/lib/url.c
index 29222926e4..fba3bd3917 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -4009,7 +4009,7 @@ static CURLcode parseurlandfillconn(struct SessionHandle *data,
       }
       else {
         /* Zone identifier is not numeric */
-#if defined(HAVE_NET_IF_H) && defined(IFNAMSIZ)
+#if defined(HAVE_NET_IF_H) && defined(IFNAMSIZ) && defined(HAVE_IF_NAMETOINDEX)
         char ifname[IFNAMSIZ + 2];
         char *square_bracket;
         unsigned int scopeidx = 0;