Use Bundler to manage vendor directory

Rather than having to manually keep track of what version each thing in
here is and copy files around by hand on update let's use Bundler's
standalone mode and careful use of `.gitignore` to help us do it.

This means a `bundle update --standalone` will allow us to update all
gems in vendor.

We could consider vendoring other gems this way in future but I'd
suggest only doing this for gems with no dependencies or at least gems
with no native extensions. The only gem this applies to that we
currently use is `ruby-prof` and I'm not convinced it's widely used
enough to warrant vendoring for everyone. Perhaps that's another
criteria: it should be functionality that's used by non-developer
commands and/or normal Homebrew usage.

.gitignore

@@ -23,6 +23,15 @@
 **/.bundle/cache
 **/vendor/bundle
 **/vendor/ruby
+**/vendor/bundle-standalone/ruby/*/cache
+**/vendor/bundle-standalone/ruby/*/gems/*/*
+**/vendor/bundle-standalone/ruby/*/specifications
+
+# Unignore vendored gems
+!**/vendor/bundle-standalone/ruby/*/gems/*/lib
+
+# Ignore backports gem (we don't need all files)
+**/vendor/bundle-standalone/ruby/*/gems/backports-*/lib
 
 # Ignore `bin` contents (again).
 /bin

Library/Homebrew/cask/artifact/pkg.rb

@@ -1,4 +1,4 @@
-require "vendor/plist/plist"
+require "plist"
 
 require "cask/artifact/abstract_artifact"
 

Library/Homebrew/extend/string.rb

@@ -1,5 +1,5 @@
 # Contains backports from newer versions of Ruby
-require_relative "../vendor/backports/string"
+require "backports/2.4.0/string/match"
 
 class String
   # String.chomp, but if result is empty: returns nil instead.

Library/Homebrew/load_path.rb

@@ -5,3 +5,5 @@ HOMEBREW_LIBRARY_PATH = Pathname(__dir__).realpath
 unless $LOAD_PATH.include?(HOMEBREW_LIBRARY_PATH.to_s)
   $LOAD_PATH.push(HOMEBREW_LIBRARY_PATH.to_s)
 end
+
+require "vendor/bundle-standalone/bundler/setup"

Library/Homebrew/os/mac/mach.rb

@@ -1,4 +1,4 @@
-require "vendor/macho/macho"
+require "macho"
 require "os/mac/architecture_list"
 
 module MachOShim

Library/Homebrew/system_command.rb

@@ -1,6 +1,6 @@
 require "open3"
 require "ostruct"
-require "vendor/plist/plist"
+require "plist"
 require "shellwords"
 
 require "extend/io"

Library/Homebrew/vendor/.bundle/config

@@ -0,0 +1,4 @@
+---
+BUNDLE_PATH: "bundle-standalone"
+BUNDLE_DISABLE_SHARED_GEMS: "true"
+BUNDLE_BIN: "false"

Library/Homebrew/vendor/Gemfile

@@ -0,0 +1,5 @@
+source "https://rubygems.org"
+
+gem "backports"
+gem "plist"
+gem "ruby-macho"

Library/Homebrew/vendor/Gemfile.lock

@@ -0,0 +1,17 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    backports (3.8.0)
+    plist (3.3.0)
+    ruby-macho (2.0.0)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  backports
+  plist
+  ruby-macho
+
+BUNDLED WITH
+   1.16.4

Library/Homebrew/vendor/bundle-standalone/bundler/setup.rb

@@ -0,0 +1,9 @@
+require 'rbconfig'
+# ruby 1.8.7 doesn't define RUBY_ENGINE
+ruby_engine = defined?(RUBY_ENGINE) ? RUBY_ENGINE : 'ruby'
+ruby_version = RbConfig::CONFIG["ruby_version"]
+path = File.expand_path('..', __FILE__)
+$:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/backports-3.8.0/lib"
+$:.unshift "#{path}/"
+$:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/plist-3.3.0/lib"
+$:.unshift "#{path}/../#{ruby_engine}/#{ruby_version}/gems/ruby-macho-2.0.0/lib"

Library/Homebrew/vendor/bundle-standalone/ruby/2.3.0/gems/backports-3.8.0/lib/backports/2.4.0/string/match.rb

@@ -1,4 +1,3 @@
-# Taken from https://github.com/marcandre/backports/blob/v3.8.0/lib/backports/2.4.0/string/match.rb
 unless String.method_defined? :match?
   class String
     def match?(*args)

Library/Homebrew/vendor/bundle-standalone/ruby/2.3.0/gems/plist-3.3.0/lib/plist.rb

@@ -13,9 +13,9 @@ require 'base64'
 require 'cgi'
 require 'stringio'
 
-require_relative 'plist/generator'
-require_relative 'plist/parser'
-require_relative 'plist/version'
+require 'plist/generator'
+require 'plist/parser'
+require 'plist/version'
 
 module Plist
 end