diff --git a/pkgs/development/compilers/ocaml/ber-metaocaml.nix b/pkgs/development/compilers/ocaml/ber-metaocaml.nix
index edb3c2e385f65..0825c2db66031 100644
--- a/pkgs/development/compilers/ocaml/ber-metaocaml.nix
+++ b/pkgs/development/compilers/ocaml/ber-metaocaml.nix
@@ -2,10 +2,10 @@
 , ncurses
 , libX11, xorgproto, buildEnv
 , fetchpatch
+, useX11 ? stdenv.hostPlatform.isx86
 }:
 
 let
-   useX11 = stdenv.hostPlatform.isx86;
    x11deps = [ libX11 xorgproto ];
    inherit (lib) optionals;