diff --git a/pkgs/by-name/ac/acme/package.nix b/pkgs/by-name/ac/acme/package.nix
index 3fb043ad15b7..8131a6dcdd99 100644
--- a/pkgs/by-name/ac/acme/package.nix
+++ b/pkgs/by-name/ac/acme/package.nix
@@ -18,7 +18,7 @@ stdenv.mkDerivation (finalAttrs: {
 
   postPatch = ''
     substituteInPlace Makefile \
-      --replace "= gcc" "?= gcc"
+      --replace-fail "= gcc" "?= gcc"
   '';
 
   enableParallelBuilding = true;