diff --git a/mozilla/configure b/mozilla/configure
index 806b70e276d..411b1af6e6e 100755
--- a/mozilla/configure
+++ b/mozilla/configure
@@ -7694,7 +7694,7 @@ else
 fi
 done
 
-for ac_func in nl_langinfo strtok_r
+for ac_func in nl_langinfo strtok_r flockfile
 do
 echo $ac_n "checking for $ac_func""... $ac_c" 1>&6
 echo "configure:7701: checking for $ac_func" >&5