(leap_year_v_p): new macro.
  (TIME_FIXOFF_P): new macro.
  (TIME_SET_FIXOFF): new macro.
  (time_init_0): renamed from time_init.
  (time_set_utc_offset): new function.
  (vtm_add_offset): new function.
  (utc_offset_arg): new function.
  (time_init_1): new function.
  (time_init): call time_init_0 or time_init_1 according argc.
  (validate_utc_offset): new function.
  (time_localtime_m): new function.
  (time_fixoff): new function.
  (time_getlocaltime): take optional UTC offset argument.
  (time_get_tm): support fixed UTC offset time.
  (Init_Time): make Time#{initialize,localtime,getlocal} varargs.

* strftime.c (rb_strftime): vtm->zone can be NULL now.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@23415 b2dd03c8-39d4-4d8f-98ff-823fe69b080e