bug#11256: make check problems with coreutils 8.16 and earlier

[Jim Meyering]

Andreas Schwab wrote:

> Jim Meyering <address@hidden> writes:
>
>> Oddly, with GNU bash, version 4.2.24(1)-release (x86_64-redhat-linux-gnu)
>> "export -fn date" does not "unexport" the date function.
>
> Are you sure?
>
> $ date () { :; }; export -f date; bash -c 'type date'; export -fn
> date; bash -c 'type date'
> date is a function
> date ()
> {
>     :
> }
> date is /bin/date

You're right: export -fn does do what it says.
Now the question is whether to make every shell-based test attempt to do
that.