1) fixed a bug that could crash df, mount, and umount applets if the root
device name was longer then the word "root" (/dev/loop1 vs /dev/root) -
2) severl functions needed static declaration in the umount applet
3) update declaration for function in last_char_is() in libbb
for 'which'. I ageed, so I whipped this up -- which revealed a bug in
concat_path_file. It turns out that that a '/' can be appended from
either the path _or_ the filename, but only the former was checked.
-Erik
