diff --git a/pkgs/by-name/uh/uhexen2/package.nix b/pkgs/by-name/uh/uhexen2/package.nix
index d12906454201..bfe2ec3750c6 100644
--- a/pkgs/by-name/uh/uhexen2/package.nix
+++ b/pkgs/by-name/uh/uhexen2/package.nix
@@ -45,7 +45,7 @@ stdenv.mkDerivation {
     )
   '';
 
-  NIX_CFLAGS_COMPILE = "-std=gnu17";
+  env.NIX_CFLAGS_COMPILE = "-std=gnu17";
 
   buildPhase = ''
     runHook preBuild