Jim Meyering wrote:
> There are still numerous unguarded [-1] references, so this updated
> patch is doubtless still incomplete:

The real bug was elsewhere, I think. I installed the attached patch. This patch 
lacks your test case, which didn't work for me because there is no 
require_valgrind_ in diffutils. Is require_valgrind_ from coreutils or from some 
other location?