internal shared string. [ruby-dev:21601]
* string.c (rb_str_new4): ditto.
* eval.c: use EXIT_SUCCESS and EXIT_FAILURE for exit values.
* process.c: ditto. [ruby-dev:38521]
* lib/debug.rb (debug_command): should enter emacs mode when
assigned any value to the environment variable "EMACS".
On Meadow, (getenv "EMACS") is "meadow".
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@4749 b2dd03c8-39d4-4d8f-98ff-823fe69b080e