Use `url-retrieve-synchronously' dependendently

Emacs 24.3 supposedly does not have a second argument to
`url-retrieve-synchronously'.  Introduce a switch dependent on
`emacs-minor-version'.

This hopefully fixes the url- issue.

1 files changed, 1 insertions, 0 deletions

diff --git a/Cask b/Cask
index a715b2a..f5be811 100644
--- a/Cask
+++ b/Cask
@@ -6,6 +6,7 @@
 (files "stack-*.el")
 
 (depends-on "json" "1.4")
+(depends-on "url")
 
 (development
  (depends-on "ert"))