diff --git a/pkgs/desktops/kde-4.6/support/qca2/default.nix b/pkgs/desktops/kde-4.6/support/qca2/default.nix
index a55f7c8cb431..1ddbf40d15eb 100644
--- a/pkgs/desktops/kde-4.6/support/qca2/default.nix
+++ b/pkgs/desktops/kde-4.6/support/qca2/default.nix
@@ -6,7 +6,8 @@ stdenv.mkDerivation {
     url = http://delta.affinix.com/download/qca/2.0/qca-2.0.2.tar.bz2;
     sha256 = "49b5474450104a2298747c243de1451ab7a6aeed4bf7df43ffa4b7128a2837b8";
   };
-  buildInputs = [ which qt4 ];
+  buildInputs = [ qt4 ];
+  buildNativeInputs = [ which ];
   preBuild = ''
     sed -i include/QtCrypto/qca_publickey.h -e '/EMSA3_Raw/a,\
             EMSA3_SHA224,     ///< SHA224, with EMSA3 (ie PKCS#1 Version 1.5) encoding\
diff --git a/pkgs/desktops/kde-4.6/support/qca2/ossl.nix b/pkgs/desktops/kde-4.6/support/qca2/ossl.nix
index bfaa320618c7..1e0c583b7a5d 100644
--- a/pkgs/desktops/kde-4.6/support/qca2/ossl.nix
+++ b/pkgs/desktops/kde-4.6/support/qca2/ossl.nix
@@ -1,4 +1,4 @@
-{stdenv, fetchurl, fetchsvn, qt4, qca2, openssl}:
+{stdenv, fetchurl, fetchsvn, qt4, qca2, openssl, which}:
 
 stdenv.mkDerivation rec {
   version = "2.0.0-beta3";
@@ -15,6 +15,7 @@ stdenv.mkDerivation rec {
     sha256 =  "ef2c0307e8834e1e7cb23b6fea1cc22486328a37186301a6c11161b1c93d834b";
   };
   buildInputs = [ qt4 qca2 openssl ];
+  buildNativeInputs = [ which ];
   dontAddPrefix = true;
   configureFlags="--no-separate-debug-info --with-qca=${qca2}
     --with-openssl-inc=${openssl}/include --with-openssl-lib=${openssl}/lib";