* eval.c (set_method_visibility): should have clear cache forq
  updated visibility.

* numeric.c (flo_to_s): default format precision to be "%.16g".

* util.c (ruby_strtod): use own strtod(3) implementation to avoid
  locale hell.  Due to this change "0xff".to_f no longer returns 255.0

* eval.c (avalue_to_yvalue): new function to distinguish yvalue
  (no-arg == Qundef) from svalue (no-arg == Qnil).

* eval.c (rb_yield_0): use avalue_to_yvalue().

* eval.c (assign): warn if val == Qundef where it means rhs is
  void (e.g. yield without value or call without argument).

* parse.y (value_expr): need not to warn for WHILE and UNTIL,
  since they can have return value (via valued break).


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@2457 b2dd03c8-39d4-4d8f-98ff-823fe69b080e