diff --git a/pkgs/by-name/fc/fcrackzip/package.nix b/pkgs/by-name/fc/fcrackzip/package.nix
index 4d89ece7d0ca..b90f8b92565f 100644
--- a/pkgs/by-name/fc/fcrackzip/package.nix
+++ b/pkgs/by-name/fc/fcrackzip/package.nix
@@ -12,7 +12,7 @@ stdenv.mkDerivation (finalAttrs: {
     sha256 = "0l1qsk949vnz18k4vjf3ppq8p497966x4c7f2yx18x8pk35whn2a";
   };
 
-  CFLAGS = "-std=gnu89";
+  env.CFLAGS = "-std=gnu89";
 
   # 'fcrackzip --use-unzip' cannot deal with file names containing a single quote
   # https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=430387