--- racc.orig/test/helper.rb
+++ racc/test/helper.rb
@@ -81,7 +81,8 @@ module Racc
     def ruby arg
       Dir.chdir(TEST_DIR) do
         Tempfile.open 'test' do |io|
-          cmd = "#{ENV['_']} -I #{INC} #{arg} 2>#{io.path}"
+          cmd = File.symlink?("/proc/#{$$}/exe") ? File.readlink("/proc/#{$$}/exe") : ENV['_']
+          cmd = "#{cmd} -I #{INC} #{arg} 2>#{io.path}"
           result = system(cmd)
           assert(result, io.read)
         end
