Look in the right place for ruby headers, and silence the warnings about
the use of the Config module.

This is an in-house patch, and has not been submitted upstream, since the
Config->RbConfig change has already been made in a newer version, and the
remainder of the changes are Solaris-specific.

--- graphviz-2.28.0/config/config_ruby.rb	Fri Feb 18 13:25:56 2011
+++ graphviz-2.28.0/config/config_ruby.rb	Tue Jul  1 14:45:16 2014
@@ -1,16 +1,16 @@
 require 'rbconfig'
 
-CONFIG = Config::MAKEFILE_CONFIG
+CONFIG = RbConfig::MAKEFILE_CONFIG
 
 
 case ARGV[0]
 when "INCLUDES"
-    puts Config::expand(CONFIG["archdir"])
+    puts "#{RbConfig::expand(CONFIG['rubyhdrdir'])} -I#{RbConfig::expand(CONFIG['rubyhdrdir'])}/#{RbConfig::expand(CONFIG['arch'])}"
 when "lib"
-    puts Config::expand(CONFIG["libdir"])
+    puts RbConfig::expand(CONFIG["libdir"])
 when "archsitelib"
-    puts Config::expand(CONFIG["sitearchdir"])
+    puts RbConfig::expand(CONFIG["vendorarchdir"])
 when "sitelib"
-    puts Config::expand(CONFIG["sitedir"])
+    puts RbConfig::expand(CONFIG["vendordir"])
 end