diff --git a/pkgs/by-name/li/libfaketime/package.nix b/pkgs/by-name/li/libfaketime/package.nix
index cf5c047850da..ecdb04678b32 100644
--- a/pkgs/by-name/li/libfaketime/package.nix
+++ b/pkgs/by-name/li/libfaketime/package.nix
@@ -55,7 +55,7 @@ stdenv.mkDerivation (finalAttrs: {
   env = {
     PREFIX = placeholder "out";
     LIBDIRNAME = "/lib";
-    NIX_CFLAGS_COMPILE = toString (
+    CFLAGS = toString (
       lib.optionals stdenv.cc.isClang [
         "-Wno-error=cast-function-type"
         "-Wno-error=format-truncation"