convention that the only undocumented externs are prefixed with
S_.
externs.h, stats.c, thread.c
original commit: 898c3941d807a18c393a4575a72283e3671ee7e5
Accesses existing-but-hidden DST information in date records,
and adds support for getting a name of the current time zone
when a time zone offset is not explicitly provided.
original commit: 3c8be62d12a8197018fb6c5aae182fd75da14fe8
structure on windows does not have the tm_gmtoff field used in the
mac and linux version of the code.
stats.c
original commit: 4339b856d85de4c949ef7c4e66ec679512809a58
