diff --git a/pkgs/servers/http/openresty/default.nix b/pkgs/servers/http/openresty/default.nix
index f527e6a6adb3..8e60573f4a51 100644
--- a/pkgs/servers/http/openresty/default.nix
+++ b/pkgs/servers/http/openresty/default.nix
@@ -49,7 +49,7 @@ callPackage ../nginx/generic.nix args rec {
     patchShebangs configure bundle/
   '';
 
-  configureFlags = lib.optional withPostgres [ "--with-http_postgres_module" ];
+  configureFlags = lib.optionals withPostgres [ "--with-http_postgres_module" ];
 
   postInstall = ''
     ln -s $out/luajit/bin/luajit-2.1.ROLLING $out/bin/luajit-openresty