lib/racc/parser.rb: use require for racc/cparse

* lib/racc/parser.rb: reverted r65505.  require_relative does
  not work for racc/cparse.so, as extension libraries are placed
  in other directories than Ruby libraries.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65514 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/racc/parser.rb

@@ -187,7 +187,7 @@ class Parser
     Racc_Runtime_Core_Version_R = '1.4.6'
     Racc_Runtime_Core_Revision_R = %w$originalRevision: 1.8 $[1]
     begin
-      require_relative 'cparse'
+      require 'racc/cparse'
     # Racc_Runtime_Core_Version_C  = (defined in extension)
       Racc_Runtime_Core_Revision_C = Racc_Runtime_Core_Id_C.split[2]
       unless new.respond_to?(:_racc_do_parse_c, true)