Unforce builder from AS

Signed-off-by: José Valim <jose.valim@gmail.com>

actionpack/actionpack.gemspec

@@ -21,6 +21,7 @@
 
   s.add_dependency('activesupport', version)
   s.add_dependency('activemodel',   version)
+  s.add_dependency('builder',       '~> 2.1.2')
   s.add_dependency('i18n',          '~> 0.4.0')
   s.add_dependency('rack',          '~> 1.1.0')
   s.add_dependency('rack-test',     '~> 0.5.4')

activemodel/activemodel.gemspec

@@ -20,5 +20,6 @@
   s.has_rdoc = true
 
   s.add_dependency('activesupport', version)
+  s.add_dependency('builder',       '~> 2.1.2')
   s.add_dependency('i18n',          '~> 0.4.0')
 end

activesupport/activesupport.gemspec

@@ -19,6 +19,5 @@
 
   s.has_rdoc = true
 
-  s.add_dependency('builder',         '~> 2.1.2')
   s.add_dependency('memcache-client', '>= 1.7.5')
 end

activesupport/lib/active_support/builder.rb

@@ -0,0 +1,6 @@
+begin
+  require 'builder'
+rescue LoadError => e
+  $stderr.puts "You don't have builder installed in your application. Please add it to your Gemfile and run bundle install"
+  raise e
+end

activesupport/lib/active_support/core_ext/array/conversions.rb

@@ -134,7 +134,7 @@ def to_formatted_s(format = :default)
   #   </messages>
   #
   def to_xml(options = {})
-    require 'builder' unless defined?(Builder)
+    require 'active_support/builder' unless defined?(Builder)
 
     options = options.dup
     options[:indent]  ||= 2

activesupport/lib/active_support/core_ext/hash/conversions.rb

@@ -55,7 +55,7 @@ class Hash
   # configure your own builder with the <tt>:builder</tt> option. The method also accepts
   # options like <tt>:dasherize</tt> and friends, they are forwarded to the builder.
   def to_xml(options = {})
-    require 'builder' unless defined?(Builder)
+    require 'active_support/builder' unless defined?(Builder)
 
     options = options.dup
     options[:indent]  ||= 2