# Usage: $teed_fh = tee @output_handles;
# Returns a new filehandle that, when written, copies to all @output_handles
sub tee {
	use vars qw(*__TEE_FH);
	my $tfh = do { \local *__TEE_FH }; # XXX Should use IO::Handle instead
	defined( my $pid = open($tfh, "|-") ) or die "fork: $!";
	return select((select($tfh), $| = 1)[0]) if $pid;
	for (@_) { select($_); $| = 1 }
	while( sysread(STDIN, my $block, 8192) ) { print $_ $block for @_ }
	kill 9,$$ or exit; # XXX Should use POSIX::_exit instead
}