The Tor Browser / file revision

 #!/usr/bin/perl -w

 #

 # This Source Code Form is subject to the terms of the Mozilla Public

 # License, v. 2.0. If a copy of the MPL was not distributed with this

 # file, You can obtain one at http://mozilla.org/MPL/2.0/.

 #

 # List the missing symbols (or, do a set difference).

 #

 use 5.004;

 use strict;

 use Getopt::Long;

 $::opt_help = 0;

 $::opt_defined = "mozilla-bin.order";

 GetOptions("help", "defined=s");

 if ($::opt_help) {

     die "usage: missing-syms.pl --defined=<file> <symlist>";

 }

 $::Defined = { };

 open(DEFINED, "<$::opt_defined") || die "couldn't open defined symbol list $::opt_defined";

 while (<DEFINED>) {

     chomp;

     $::Defined{$_} = 1;

 }

 close(DEFINED);

 while (<>) {

     chomp;

     print "$_\n" unless ($::Defined{$_});

 }