Given that the bug report suggests only the is_W() function is used from FileHandle::Fmode I don't see why you can't replace the entire dependency with this short sub:
sub is_W {
my $fh = shift;
return 0 unless defined $fh;
return 0 unless defined fileno $fh;
local $\ = ''; # just in case
no warnings; # temporarily disable warnings
#my ($atime,$mtime) = (stat($fh))[8,9];
my $is_w = print $fh '';
#eval{ utime $atime, $mtime, $fh }; # can fail if futimes not avai
+lable
return $is_w;
}
my $file = "C:/tmp.txt";
printf "Null fh %d\n", is_W();
open F, ">", $file or die "Can't create $file $!\n";
printf "Writable fh %d\n", is_W(*F);
close F;
open F, $file or die "Can't create $file $!\n";
printf "Readable fh %d\n", is_W(*F);
close F;
printf "STDIN %d\n", is_W(*STDIN);
printf "STDOUT %d\n", is_W(*STDOUT);
printf "STDERR %d\n", is_W(*STDERR);
__DATA__
Null fh 0
Writable fh 1
Readable fh 0
STDIN 0
STDOUT 1
STDERR 1
Update added "no warnings;" as per barts suggestion. Added comments containing mtime restoration code (if desired) also per bart.