diff --git a/pkgs/by-name/p1/p11-kit/package.nix b/pkgs/by-name/p1/p11-kit/package.nix
index cd041289a6a2..316265e07bef 100644
--- a/pkgs/by-name/p1/p11-kit/package.nix
+++ b/pkgs/by-name/p1/p11-kit/package.nix
@@ -60,7 +60,7 @@ stdenv.mkDerivation rec {
     ]))
   ];
 
-  mesonCheckFlags = lib.optionals (stdenv.buildPlatform.isDarwin && stdenv.buildPlatform.isx86_64) [
+  ${if stdenv.buildPlatform.isDarwin && stdenv.buildPlatform.isx86_64 then "mesonCheckFlags" else null} = [
     # Tests regularly exceed the default timeout on `x86_64-darwin`.
     "--timeout-multiplier=0"
   ];