diff --git a/pkgs/tools/misc/rrdtool/default.nix b/pkgs/tools/misc/rrdtool/default.nix
index b03cd4a9a7e6..58070c3b1b1c 100644
--- a/pkgs/tools/misc/rrdtool/default.nix
+++ b/pkgs/tools/misc/rrdtool/default.nix
@@ -1,5 +1,5 @@
 { fetchurl, lib, stdenv, gettext, perl, pkg-config, libxml2, pango, cairo, groff
-, tcl-8_5, darwin }:
+, tcl, darwin }:
 
 perl.pkgs.toPerlModule (stdenv.mkDerivation rec {
   pname = "rrdtool";
@@ -13,7 +13,7 @@ perl.pkgs.toPerlModule (stdenv.mkDerivation rec {
   nativeBuildInputs = [ pkg-config ];
 
   buildInputs = [ gettext perl libxml2 pango cairo groff ]
-    ++ lib.optionals stdenv.isDarwin [ tcl-8_5 darwin.apple_sdk.frameworks.ApplicationServices ];
+    ++ lib.optionals stdenv.isDarwin [ tcl darwin.apple_sdk.frameworks.ApplicationServices ];
 
   postInstall = ''
     # for munin and rrdtool support