gds-cli.diff

diff --git a/Formula/gds-cli.rb b/Formula/gds-cli.rb
index bddbfa7..b315cc0 100644
--- a/Formula/gds-cli.rb
+++ b/Formula/gds-cli.rb
@@ -9,7 +9,10 @@ class GdsCli < Formula
 
   depends_on "go" => :build
   depends_on "awscli"
-  depends_on "aws-vault" if OS.linux?
+
+  on_linux do
+    depends_on "aws-vault"
+  end
 
   def install
     system "make"
@@ -23,9 +26,9 @@ class GdsCli < Formula
   end
 
+  on_macos do
+    def caveats
+      "gds-cli depends on aws-vault being installed.  You can install it with `brew cask install aws-vault`."
+    end
   end
 
   test do