Alas, while the current tz package can get the day-skipping part of the Julian-to-Gregorian calendar transition right, it gets pre-transition weekdays worng.

(Getting them right would require special casing for big offsets from standard time in localtime.c)

    @dashdashado

Script started on Sat, Nov 10, 2018  6:47:15 PM
$ cat fake
Zone America/Somewhere    -268:56:02 -    LMT    1752 Sep 3
            -4:56:02 -    LMT
$ ./zic fake
$ ./zdump -v America/Somewhere
America/Somewhere  -9223372036854775808 = NULL
America/Somewhere  -9223372036854689408 = NULL
America/Somewhere  Thu Sep 14 04:56:01 1752 UT = Sat Sep  2 23:59:59 1752 LMT isdst=0 gmtoff=-968162
America/Somewhere  Thu Sep 14 04:56:02 1752 UT = Thu Sep 14 00:00:00 1752 LMT isdst=0 gmtoff=-17762
America/Somewhere  9223372036854689407 = NULL
America/Somewhere  9223372036854775807 = NULL
$ exit
exit

Script done on Sat, Nov 10, 2018  6:47:36 PM