diff --git a/pkgs/by-name/sp/spral/package.nix b/pkgs/by-name/sp/spral/package.nix
index e8f7a940e61c..bbe93f52aec5 100644
--- a/pkgs/by-name/sp/spral/package.nix
+++ b/pkgs/by-name/sp/spral/package.nix
@@ -67,7 +67,9 @@ stdenv.mkDerivation (finalAttrs: {
 
   mesonFlags = [ (lib.mesonBool "tests" true) ];
 
-  LDFLAGS = lib.optionals stdenv.hostPlatform.isDarwin [ "-lomp" ];
+  env = lib.optionalAttrs stdenv.hostPlatform.isDarwin {
+    LDFLAGS = "-lomp";
+  };
 
   doCheck = true;