added else

Rakefile

@@ -266,7 +266,8 @@ begin
             project = Xcodeproj::Project.open(project_path)
             target = project.targets.first
 
-            case target.platform_name
+            platform = target.platform_name
+            case platform
             when :osx
               execute_command "xcodebuild -workspace '#{workspace_path}' -scheme '#{scheme_name}' clean build"
             when :ios
@@ -275,6 +276,8 @@ begin
               # Specifically build against the simulator SDK so we don't have to deal with code signing.
               simulator_name = major_version > 5 ? 'iPhone 6' : 'iPhone Retina (4-inch)'
               execute_command "xcodebuild -workspace '#{workspace_path}' -scheme '#{scheme_name}' clean build ONLY_ACTIVE_ARCH=NO -destination 'platform=iOS Simulator,name=#{simulator_name}'"
+            else
+              fail "Unknown platform #{platform.to_s}"
             end
           end
         end