diff --git a/pkgs/development/tools/ocaml/cppo/default.nix b/pkgs/development/tools/ocaml/cppo/default.nix
index 55e9692a0a3b..3134c310c453 100644
--- a/pkgs/development/tools/ocaml/cppo/default.nix
+++ b/pkgs/development/tools/ocaml/cppo/default.nix
@@ -61,7 +61,7 @@ stdenv.mkDerivation {
   makeFlags = [ "PREFIX=$(out)" ];
 
   preBuild = ''
-    mkdir $out/bin
+    mkdir -p $out/bin
   '';
 
 }