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

[Paul Eggert]

Here is a shell transcript on my platform. Can you compare it to what 
happens on your platform? I am guessing that the first 'echo $?' outputs 
something different but would like to know what it is. Plus any other 
differences.

$ export LC_ALL=en_US.UTF-8
$ s_pair=$(printf '\360\220\220\205')
$ printf '%s\n' "$s_pair" > in
$ src/grep --file=in in >out
$ echo $?
0
$ od -t o1 in
0000000 360 220 220 205 012
0000005
$ cmp in out
$ echo $?
0