This has been a complicated issue to fix for a number of reasons.
The core of it is that the behavior is different between different
versions of macOS, some of which set possible-but-incorrect values.
This commit addresses the issue by always using our computation for
tm_wday and tm_yday on macOS. As a side-effect, strptime format
strings that specify %u and %j will no longer work on macOS.
Dates in 1900 are before the Unix epoch. We shouldn't make any promises
about how well they are supported, especially given that our time
support is a thin wrapper over the libc functions.
This changes the test to use dates after the epoch, which should fit
within both a signed and an unsigned 32-bit time_t.
strptime() on OS X and *BSDs (reputedly) does not set tm_wday and
tm_yday unless corresponding %U and %j format specifiers were used.
That can be... surprising when one parsed year, month, and day anyways.
Glibc's strptime() conveniently sets tm_wday and tm_yday in those cases,
but OS X's does not, ignoring them completely.
This commit makes jq compute those where possible, though the day of
week computation may be wrong for dates before 1900-03-01 or after
2099-12-31.
Use %%FAIL IGNORE MSG for error messages that differ on Windows, and
move the sort_by/group_by tests that fail qhen qsort() is not stable.
Now only tests/sorttest and tests/shtest are disabled on Windows.
