Add temporary compatibility layer for `Tty.white`.

Library/Homebrew/compat.rb

@@ -15,3 +15,4 @@ require "compat/dependency_collector"
 require "compat/language/haskell"
 require "compat/xcode"
 require "compat/software_spec"
+require "compat/utils"

Library/Homebrew/compat/utils.rb

@@ -8,3 +8,11 @@ def shell_profile
   else "~/.bash_profile"
   end
 end
+
+module Tty
+  module_function
+
+  def white
+    reset.bold
+  end
+end