[Bug-tar] Furture Timestamp corrupts time field

[Phil Roberts]

Hello, we downloaded a newly minted tar.gz archive yesterday and attempted
to compile the software after using tar 1.15.1 with -xzvf options.  When we
reached the 'MAKE' phase we encountered a loop telling us the Makefile.in
was a future date, ie no compiles were performed.  Investigating I found the
hour:minute field had been replaced by the year 2007.  This was strange as
WinZip actually showed a valid hh:mm there when I ran it to verify what was
happening.

I downloaded tar 1.16.1 and compiled it and re-ran the tar -xzvf on the
tar.gz archive.  This time I noticed some warnings about 'time stamp xxx is
xxxx s in the future'.  This is coming from extract.c check_time which
checks for 'implausibly old' or 'in the future', not a problem I guess in
itself.

The problem seems to occur when the year is extracted to the hh:mm field
instead of the 'future' hh:mm time populating it.  This is proabably a
result of the archive being created in a distant timezone where it is 10
hours or so ahead of me (WinZip seems to handle this automagically and
populates the hh:mm with valid data instead of the year).

I presume a simple test could be performed by creating a tar file with files
which have been 'touched *' to populate current time, changing the clock
back say an hour or so and using tar again to untar the archive.  This
should replicate the odd behaviour of the year being substituted for hh:mm
when future time is involved.

Whatever the reasoning for time checking, TAR shouldn't substitute timestamp
data.