bug#49983: grep-3.6.27-20b4 tests fail on Cygwin

[Gary Johnson]

On 2021-08-10, Paul Eggert wrote:
> On 8/10/21 4:21 PM, Gary Johnson wrote:
> >$ src/grep --file=in in >out
> >$ echo $?
> >1
> >$ od -t o1 in
> >0000000 360 220 220 205 012
> >0000005
> >$ cmp in out
> >cmp: EOF on out which is empty
> 
> OK, so grep is simply not finding a match.
> 
> At this point it's probably time to fire up a debugger and see why
> grep's matchers are saying "no match". That would require some
> debugging expertise and time, though; do you have those available?

I'm familiar with gdb, but not an expert.  I've used it mostly for
debugging Vim on Linux and for debugging an embedded, bare-metal
RISC-V project.  I hacked grep once to add an option to control
whether underscore was part of a word or not, but that was a long
time ago.  I don't remember anything about grep's internals.  The
main thing I'm lacking is time.  I'm married and employed full time,
though I've managed to squeeze in some time for Vim enhancements on
weekends when it's too hot and/or smokey to work outside.  I can
take a stab at it and let you know if it's taking too much time.

Regards,
Gary