bug#7223: DATE 8.5 and back -- Invalid date with specific dates

[Lucien Raven]

This problem was reproduced in several versions of 'date', and the oldest one I 
could reproduce the problem was 6.10.

But it doesn´t happen in older ones (tried on 'date' 5.97)


Examples:

# ./date +%Y --date=20101018
2010

# ./date +%Y --date=20101016
2010

# ./date +%Y --date=20101017
./date: invalid date `20101017'

# ./date +%Y --date=20101018
2010

# ./date --version
date (GNU coreutils) 8.5
Copyright (C) 2010 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

This seems to happen in several other dates:

# date +%Y%m%d --date=20101017
date: invalid date `20101017'

# date +%Y%m%d --date=20131020
date: invalid date `20131020'

# date +%Y%m%d --date=20111016
date: invalid date `20111016'

# date +%Y%m%d --date=20141019
date: invalid date `20141019'

Same command on 'date' 5.97 -- Problem only with the first date:

$ date +%Y%m%d --date=20101017
date: invalid date `20101017'

$ date +%Y%m%d --date=20131020
20131020

$ date +%Y%m%d --date=20111016
20111016

$ date +%Y%m%d --date=20141019
20141019

$ date --version
date (GNU coreutils) 5.97
Copyright (C) 2006 Free Software Foundation, Inc.
This is free software.  You may redistribute copies of it under the terms of 
the GNU General Public License <http://www.gnu.org/licenses/gpl.html>.
There is NO WARRANTY, to the extent permitted by law.

PS: The dates correspond to the third Sunday of October.