the war on trailing whitespace

It's invariably pointless to add lines which have trailing whitespace. 
Nobody cares much, but my scripts spam me when it happens, so I've become
obsessive.    Looking at Dave Miller's current net devel tree:

bix:/usr/src/25> grep '^+.*[    ]$' patches/git-net.patch | wc -l
    170

Note that this is purely _added_ trailing whitespace.  I'm not proposing
that the revision control system should care about pre-existing trailing
whitespace.

I got the quilt guys to generate warnings when patches add trailing
whitespace, and to provide the tools to strip it.  And I believe Larry made
similar changes to bk.

I realise that we cannot do this when doing git fetches, but when importing
patches and mboxes, git ought to whine loudly about input which matches the
above regexp, and it should offer an option to tidy it up.  Perhaps by
default.

Of course, this means that the person who sent the patch will find that his
as-yet-unsent patches don't apply to the upstream tree any more.  Well,
that's tough luck - perhaps it'll motivate him to stop adding trailing
whitespace.  The patches will still apply with `patch -l'.

Thanks for listening ;)