[Sample Spec] instructions on how handle pods which support both platforms with different details

lib/cocoapods/command/spec.rb

@@ -185,10 +185,14 @@ Pod::Spec.new do |s|
 
   # If this Pod runs only on iOS or OS X, then specify that with one of
   # these, or none if it runs on both platforms.
+  # If the pod runs on both plafroms but presents different deployment
+  # targets, source files, etc. create two different pods: `#{data[:name]}-iOS'
+  # and `#{data[:name]}-OSX'.
   #
   # s.platform = :ios
   # s.platform = :ios, { :deployment_target => "5.0" }
   # s.platform = :osx
+  # s.platform = :osx, { :deployment_target => "10.7" }
 
   # A list of resources included with the Pod. These are copied into the
   # target bundle with a build phase script.