df does not report my root file system

[Ming-Ching Tiew]

From: "Rob Landley" <rob at landley.net>
> 
> Yeah, df is broken.  I need to upgrade it.
> 

Instead of adding so much code logic and complexity
( sort, kill duplicates and so on ), perhaps may I
suggest we treat the current behaviour has the normal,
and just add one commandline switch to display
the mounted rootfs ( df -r or something ) as special case ?

Should probably easier and few lines.

My two cents.