Better describe X11 in brew --config

Library/Homebrew/cmd/--config.rb

@@ -52,44 +52,27 @@ module Homebrew extend self
     if sha.empty? then "(none)" else sha end
   end
 
+  def describe_path path
+    return "N/A" if path.nil?
+    realpath = path.realpath
+    if realpath == path then path else "#{path} => #{realpath}" end
+  end
+
   def describe_x11
-    return "N/A" unless x11_installed?
-    return case x11_path = Pathname.new("/usr/X11").realpath.to_s
-    when "/usr/X11" then "/usr/X11"
-    else "/usr/X11 => #{x11_path}"
-    end
+    return "N/A" unless MacOS.x11_installed?
+    return "#{MacOS.xquartz_version} @ " + describe_path(MacOS.x11_prefix)
   end
 
   def describe_perl
-    perl = which 'perl'
-    return "N/A" if perl.nil?
-
-    real_perl = Pathname.new(perl).realpath
-    return perl if perl == real_perl
-    return "#{perl} => #{real_perl}"
+    describe_path(which 'perl')
   end
 
   def describe_python
-    python = which 'python'
-    return "N/A" if python.nil?
-
-    real_python = Pathname.new(python).realpath
-
-    return python if python == real_python
-    return "#{python} => #{real_python}"
+    describe_path(which 'python')
   end
 
   def describe_ruby
-    ruby = which 'ruby'
-    return "N/A" if ruby.nil?
-
-    real_ruby = Pathname.new(ruby).realpath
-    return ruby if ruby == real_ruby
-    return "#{ruby} => #{real_ruby}"
-  end
-
-  def real_path a_path
-    Pathname.new(a_path).realpath.to_s
+    describe_path(which 'ruby')
   end
 
   def hardware