diff --git a/pkgs/development/libraries/tk/builder.sh b/pkgs/development/libraries/tk/builder.sh
index 2f036ebd66eb..999488a35310 100644
--- a/pkgs/development/libraries/tk/builder.sh
+++ b/pkgs/development/libraries/tk/builder.sh
@@ -1,5 +1,6 @@
 source $stdenv/setup
 
+configureFlags="--with-tcl=$tcl/lib"
 preConfigure() {
   cd unix
 }
diff --git a/pkgs/development/libraries/tk/default.nix b/pkgs/development/libraries/tk/default.nix
index 27d7cdc46d7b..fc7d11273aa8 100644
--- a/pkgs/development/libraries/tk/default.nix
+++ b/pkgs/development/libraries/tk/default.nix
@@ -8,4 +8,5 @@ stdenv.mkDerivation {
     md5 = "0a16d4d9398e43cbb85784c85fb807a4";
   };
   buildInputs = [tcl x11];
+  inherit tcl;
 }