Add deprecated runtime flag

Rakefile

@@ -7,7 +7,7 @@ require "execjs/runtimes"
 
 tests = namespace :test do |tests|
   ExecJS::Runtimes.names.each do |name|
-    next if name.to_s == "Disabled"
+    next if ExecJS::Runtimes.const_get(name).deprecated?
 
     task(name.downcase) do
       ENV["EXECJS_RUNTIME"] = name.to_s

lib/execjs/disabled_runtime.rb

@@ -18,6 +18,10 @@ module ExecJS
       raise Error, "ExecJS disabled"
     end
 
+    def deprecated?
+      true
+    end
+
     def available?
       true
     end

lib/execjs/external_runtime.rb

@@ -95,6 +95,7 @@ module ExecJS
       @test_args   = options[:test_args]
       @test_match  = options[:test_match]
       @encoding    = options[:encoding]
+      @deprecated  = !!options[:deprecated]
       @binary      = nil
     end
 
@@ -103,6 +104,10 @@ module ExecJS
       binary ? true : false
     end
 
+    def deprecated?
+      @deprecated
+    end
+
     private
       def binary
         @binary ||= locate_binary

lib/execjs/runtime.rb

@@ -44,6 +44,10 @@ module ExecJS
       context_class.new(self, source)
     end
 
+    def deprecated?
+      false
+    end
+
     def available?
       raise NotImplementedError
     end

lib/execjs/runtimes.rb

@@ -52,7 +52,7 @@ module ExecJS
     end
 
     def self.best_available
-      runtimes.find(&:available?)
+      runtimes.reject(&:deprecated?).find(&:available?)
     end
 
     def self.from_environment