cask: Fix cask usage

Without python as a dependency I only get the following error:
/usr/bin/env: ‘python’: No such file or directory

1 files changed, 6 insertions, 3 deletions

diff --git a/pkgs/development/tools/cask/default.nix b/pkgs/development/tools/cask/default.nix
index 8ec2552aeff..f89bd1ddf02 100644
--- a/pkgs/development/tools/cask/default.nix
+++ b/pkgs/development/tools/cask/default.nix
@@ -10,10 +10,15 @@ stdenv.mkDerivation rec {
   };
 
   doCheck = true;
+
+  nativeBuildInputs = [ emacsPackages.emacs ];
   buildInputs = with emacsPackages; [
     s f dash ansi ecukes servant ert-runner el-mock
     noflet ert-async shell-split-string git package-build
+  ] ++ [
+    python
   ];
+
   buildPhase = ''
     emacs --batch -L . -f batch-byte-compile cask.el cask-cli.el
   '';
@@ -38,11 +43,9 @@ stdenv.mkDerivation rec {
       Cask can also be used to manage dependencies for your local Emacs configuration.
     '';
 
-    homepage = https://cask.readthedocs.io/en/latest/index.html;
+    homepage = "https://cask.readthedocs.io/en/latest/index.html";
     license = licenses.gpl3Plus;
     platforms = platforms.linux;
     maintainers = [ maintainers.flexw ];
   };
-
-  nativeBuildInputs = [ emacsPackages.emacs python ];
 }