* lib/rubygems*: Updated to RubyGems 2.0

* test/rubygems*:  ditto.

* common.mk (prelude):  Updated for RubyGems 2.0 source rearrangement.

* tool/change_maker.rb:  Allow invalid UTF-8 characters in source
  files.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@37976 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/rubygems/core_ext/kernel_gem.rb

@@ -0,0 +1,53 @@
+module Kernel
+
+  # REFACTOR: This should be pulled out into some kind of hacks file.
+  remove_method :gem if 'method' == defined? gem # from gem_prelude.rb on 1.9
+
+  ##
+  # Use Kernel#gem to activate a specific version of +gem_name+.
+  #
+  # +requirements+ is a list of version requirements that the
+  # specified gem must match, most commonly "= example.version.number".  See
+  # Gem::Requirement for how to specify a version requirement.
+  #
+  # If you will be activating the latest version of a gem, there is no need to
+  # call Kernel#gem, Kernel#require will do the right thing for you.
+  #
+  # Kernel#gem returns true if the gem was activated, otherwise false.  If the
+  # gem could not be found, didn't match the version requirements, or a
+  # different version was already activated, an exception will be raised.
+  #
+  # Kernel#gem should be called *before* any require statements (otherwise
+  # RubyGems may load a conflicting library version).
+  #
+  # In older RubyGems versions, the environment variable GEM_SKIP could be
+  # used to skip activation of specified gems, for example to test out changes
+  # that haven't been installed yet.  Now RubyGems defers to -I and the
+  # RUBYLIB environment variable to skip activation of a gem.
+  #
+  # Example:
+  #
+  #   GEM_SKIP=libA:libB ruby -I../libA -I../libB ./mycode.rb
+
+  def gem(gem_name, *requirements) # :doc:
+    skip_list = (ENV['GEM_SKIP'] || "").split(/:/)
+    raise Gem::LoadError, "skipping #{gem_name}" if skip_list.include? gem_name
+
+    if gem_name.kind_of? Gem::Dependency
+      unless Gem::Deprecate.skip
+        warn "#{Gem.location_of_caller.join ':'}:Warning: Kernel.gem no longer "\
+          "accepts a Gem::Dependency object, please pass the name "\
+          "and requirements directly"
+      end
+
+      requirements = gem_name.requirement
+      gem_name = gem_name.name
+    end
+
+    spec = Gem::Dependency.new(gem_name, *requirements).to_spec
+    spec.activate if spec
+  end
+
+  private :gem
+
+end