Added bundler as default gems. Revisit [Feature #12733]

* bin/*, lib/bundler/*, lib/bundler.rb, spec/bundler, man/*:
    Merge from latest stable branch of bundler/bundler repository and
    added workaround patches. I will backport them into upstream.
  * common.mk, defs/gmake.mk: Added `test-bundler` task for test suite
    of bundler.
  * tool/sync_default_gems.rb: Added sync task for bundler.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65509 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/bundler/cli/console.rb

@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+module Bundler
+  class CLI::Console
+    attr_reader :options, :group
+    def initialize(options, group)
+      @options = options
+      @group = group
+    end
+
+    def run
+      Bundler::SharedHelpers.major_deprecation 2, "bundle console will be replaced " \
+                           "by `bin/console` generated by `bundle gem <name>`"
+
+      group ? Bundler.require(:default, *(group.split.map!(&:to_sym))) : Bundler.require
+      ARGV.clear
+
+      console = get_console(Bundler.settings[:console] || "irb")
+      console.start
+    end
+
+    def get_console(name)
+      require name
+      get_constant(name)
+    rescue LoadError
+      Bundler.ui.error "Couldn't load console #{name}, falling back to irb"
+      require "irb"
+      get_constant("irb")
+    end
+
+    def get_constant(name)
+      const_name = {
+        "pry"  => :Pry,
+        "ripl" => :Ripl,
+        "irb"  => :IRB,
+      }[name]
+      Object.const_get(const_name)
+    rescue NameError
+      Bundler.ui.error "Could not find constant #{const_name}"
+      exit 1
+    end
+  end
+end