diff --git a/pkgs/by-name/lc/lcalc/package.nix b/pkgs/by-name/lc/lcalc/package.nix
index e29277b96f37..64f591d9f107 100644
--- a/pkgs/by-name/lc/lcalc/package.nix
+++ b/pkgs/by-name/lc/lcalc/package.nix
@@ -19,6 +19,10 @@ stdenv.mkDerivation (finalAttrs: {
     hash = "sha256-L9502+lwSPLk63C14Pxa8OZWhnY4OqKv9WudZO2vP7E=";
   };
 
+  # upstream ships a patched ltmain.sh from libtool 2.5.4. the patch
+  # is already included in libtool 2.6.1.
+  postPatch = "sed -i '/ltmain.sh/d' configure.ac";
+
   nativeBuildInputs = [
     autoreconfHook
     gengetopt