bug#12772: date : Bug in handling human readable dates

[Guido Ackermann]

Hello,
today i discovered a bug in the programm "date" handling human readable 
timeformats.
The bug:

# date --version
date (GNU coreutils) 8.5

# export LC_ALL="C" ;date
Wed Oct 31 10:57:06 CET 2012
# export LC_ALL="C" ;date -d"last month"
Mon Oct  1 11:57:23 CEST 2012
# export LC_ALL="C" ;date -d"next month"
Sat Dec  1 10:57:35 CET 2012

While aktual monthh is still Oct, previous month is shown as Oct too, and next 
month is shown as Dec.
Correctly "last month" should be Sep. "next month" should be Nov. 

regards,
        Guido Ackermann