bug#11900: Sort by month fails if not in first field or first position

[jim]

If I put a month in any column other than the first, at any position than the 
first, sort fails-

> echo -e "1 qFeb\n1 qJan" | sort -k2.2,2.5M
1 qFeb
1 qJan

The following all *DO* work, however:


#First column, not first position
> echo -e "qFeb\nqJan" | sort -k1.2,1.5M
qJan
qFeb

#Second column, first position
> echo -e "1 Feb\n1 Jan" | sort -k2.1,2.4M
1 Jan
1 Feb

#Second column, full key
> echo -e "1 Feb\n1 Jan" | sort -k2M
1 Jan
1 Feb