use strict;
use warnings;
use File::Copy;

File::Copy::copy('Tcl.dll', 'Tcl.dll_bak') or die $!;
open my $infh, '<', 'Tcl.dll' or die $!;
open my $outfh, '>', 'Tcl.dll_new' or die $!;
binmode($infh);
binmode($outfh);
while(<$infh>) {
  $_ =~ s/zlib1\.dll/zxxxx.dll/g;
  print $outfh, $_;
}