diff --git a/pkgs/development/ocaml-modules/fontconfig/default.nix b/pkgs/development/ocaml-modules/fontconfig/default.nix
index 4f586f2f99e0..ce17cc60ebf8 100644
--- a/pkgs/development/ocaml-modules/fontconfig/default.nix
+++ b/pkgs/development/ocaml-modules/fontconfig/default.nix
@@ -11,7 +11,10 @@ stdenv.mkDerivation {
 
   nativeBuildInputs = [ pkgconfig ];
   buildInputs = [ ocaml fontconfig ];
-  makeFlags = "OCAML_STDLIB_DIR=$(out)/lib/ocaml/${stdenv.lib.getVersion ocaml}/site-lib/ OCAML_HAVE_OCAMLOPT=yes";
+  makeFlags = [
+    "OCAML_STDLIB_DIR=$(out)/lib/ocaml/${stdenv.lib.getVersion ocaml}/site-lib/"
+    "OCAML_HAVE_OCAMLOPT=yes"
+  ];
 
   meta = {
     description = "Fontconfig bindings for OCaml";