Historically, to work around CVS limitations, imports on the tzcode
vendor branch were split into subdirectories, which were then merged to
their respective counterparts in contrib.  In the Git era, this split is
unnecessary and adds more work.

Undo the split for the most recent vendor import of tzcode 2010n to
prepare for the vendor import of tzcode 2022c.

* Makefile        Change LOCALTIME default from "Factory" to "GMT";
                  do not compile "factory" file
                  (but keep it in the distribution).
* Theory          Remove reference to "Factory" zone.
* localtime.c     Initialize ttinfo structures filled by tzparse
                  (thanks to Ravindra for reporting a valgrind warning).
* zic.c           Fix generation of POSIX strings for zones with
                  rules using "weekday<=n" forms of dates
                  (thanks to Lei Liu for finding the problem).
                  Also, limit output for non-POSIX-specificable zones
                  defined to follow the same rules every year.
                  (Note that no zones of either of the above types
                  appear in the distribution; these changes cater to
                  add-on zones).

Obtained from:	ftp://elsie.nci.nih.gov/pub/

Obtained from:	ftp://elsie.nci.nih.gov/pub/

- Updated quotes and links.
- Put warning about case insensitivity of names, but not always in
  abbreviations.

localtime.c - more core dump avoidance work

  * asctime.c - Set errno to EINVAL and return
    "??? ??? ?? ??:??:?? ????\n"
    if asctime_r is called with a NULL struct tm pointer.
    (Note that asctime_r is called by ctime_r and asctime;
    asctime is called by ctime.)
  * localtime.c - Set errno to EINVAL and return WRONG
    if time1 is called with a NULL struct tm pointer;
    avoid dereference if a NULL struct tm pointer is
    passed to timelocal, timegm, or timeoff.
    (Note that time1 is called by mktime,
    timegm, and timeoff; mktime is called by timelocal.)

Obtained from:	ftp://elsie.nci.nih.gov/pub/

Unused:
- Updates to tz-link.html and tz-art.htm
- Typo in tzfile.5.txt

zic:
- Fix URL / reference to Calendrical Calculations: Third Edition

libc/stdtime:
- Fix typo in tzfile.5

- Extra links in unused/tz-link.htm

Obtained from:	ftp://elsie.nci.nih.gov/pub/