Raw ideas:

• $SIG{__WARN__}=sub {
      warn substr($_[0],0,100)
  };
  $SIG{__DIE__}=sub {
      die substr($_[0],0,100) # unless in eval ...
  };
  [download]

• tie *STDERR,'Test::JustShutup'; # Test::JustShutup to be written ... ;-)
• IO::Capture::Stderr (using a tie behind the scenes)

• my $null=File::Spec->devnull();
  open STDERR,'>',$null or die "Could not open '$null': $!";
  # no close() before open(), open() takes care of closing STDERR at the
  + right time
  [download]

Alexander