diff --git a/pkgs/applications/virtualization/virtualbox/default.nix b/pkgs/applications/virtualization/virtualbox/default.nix
index 66d165d09a72..6c15b2ea2ced 100644
--- a/pkgs/applications/virtualization/virtualbox/default.nix
+++ b/pkgs/applications/virtualization/virtualbox/default.nix
@@ -31,7 +31,7 @@ let
       url = "https://acpica.org/sites/acpica/files/acpica-unix-${version}.tar.gz";
       sha256 = "0bqhr3ndchvfhxb31147z8gd81dysyz5dwkvmp56832d0js2564q";
     };
-    NIX_CFLAGS_COMPILE = old.NIX_CFLAGS_COMPILE ++ [ "-Wno-error=stringop-truncation" ];
+    NIX_CFLAGS_COMPILE = old.NIX_CFLAGS_COMPILE + " -Wno-error=stringop-truncation";
   });
 in stdenv.mkDerivation {
   pname = "virtualbox";