What to do about setup's poor handling of disk full conditions

[Christopher Faylor <cgf-use-the-mailinglist-please at cygwin dot com>]

I keep cygwin on a partition which is relatively small.  So, today for
at least the third time, I've run into problems where setup was unable
to extract files because I'd run out of disk space (I had started to
install the 64-bit installation on the same disk, thought better of it,
and forgotten to clean up after myself).  The errors represented as
in-use problems.  That was clearly wrong.  I thought there was a setup
bug because it seemed to allow me to continue without error.  It didn't
really.  I kept continuing until eventually setup came to a hard stop
and my installation was hosed.

What should setup do when it encounters a full disk?  I think it should
probably give the user the option of freeing up disk space and
continuing but I think that's going to be difficult to do cleanly since
there are any number of places where you could run into this situation.

Does anyone have any creative ideas about how to allow setup.exe to
cleanly handle out-of-disk-space errors?

cgf