Ruby

merges r21079 from trunk into ruby_1_9_1.

• vm.c (Init_VM): create and define TOPLEVEL_BINDING at first.
• vm.c (vm_set_main_stack, rb_iseq_eval_main): added.
• parse.y (rb_parser_compile_file): fix to check parse_in_eval flag.
• eval.c (ruby_exec_node): use rb_iseq_eval_main()
  instead of rb_iseq_eval().
• iseq.c (rb_iseq_new_main), vm_core.h: added.
  main script (specified by -e or script name) should be run
  under TOPLEVEL_BINDING using Kernel#eval. Above changes
  simulate Kernel#eval behaviour. [ruby-dev:37240]
• compile.c (make_name_for_block): skip iseq except block type.
  this fix is needed for [ruby-dev:37240], and also fixes
  [ruby-dev:35392].

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_1@21083 b2dd03c8-39d4-4d8f-98ff-823fe69b080e