diff --git a/pkgs/development/compilers/chicken/4/eggDerivation.nix b/pkgs/development/compilers/chicken/4/eggDerivation.nix
index 7e334782fe78..a4eb19b8a927 100644
--- a/pkgs/development/compilers/chicken/4/eggDerivation.nix
+++ b/pkgs/development/compilers/chicken/4/eggDerivation.nix
@@ -26,10 +26,13 @@ stdenv.mkDerivation (
     nativeBuildInputs = [ makeWrapper ];
     buildInputs = [ chicken ];
 
-    CSC_OPTIONS = lib.concatStringsSep " " cscOptions;
+    env = {
+      CSC_OPTIONS = lib.concatStringsSep " " cscOptions;
 
-    CHICKEN_REPOSITORY = libPath;
-    CHICKEN_INSTALL_PREFIX = "$out";
+      CHICKEN_REPOSITORY = libPath;
+      CHICKEN_INSTALL_PREFIX = "$out";
+    }
+    // (args.env or { });
 
     installPhase = ''
       runHook preInstall