* file.c (rb_find_file_ext_safe, rb_find_file_safe): default to
  US-ASCII for encdb and transdb.

* load.c (search_required): keep encoding of feature name.  set
  loading path to filesystem encoding.  [Bug #6377][ruby-core:44750]

* ruby.c (add_modules, require_libraries): assume default external
  encoding as well as ARGV.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_3@37209 b2dd03c8-39d4-4d8f-98ff-823fe69b080e