empty path, just ignore.

* dir.c: remove <sys/parm.h> inclusion.

* compar.c (cmp_eq,cmp_gt,cmp_ge,cmp_lt,cmp_le): check using
  rb_cmpint().

* error.c (init_syserr): remove sys_nerr dependency.

* numeric.c (num_cmp): added to satisfy Comparable assumption.

* eval.c (rb_add_method): "initialize" should be public if it is a
  singleton method.

* regex.c (re_match): avoid dereferencing if size == 0.
  (ruby-bugs-ja:PR#360)

* time.c (time_cmp): should return nil if an operand is not a
  number nor time. (ruby-bugs-ja:PR#359)

* file.c (rb_stat_cmp): should return nil if an operand is not
  File::Stat.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@3076 b2dd03c8-39d4-4d8f-98ff-823fe69b080e