use Thread::Semaphore qw( );
use threads::shared   qw( is_shared );

BEGIN {
   package Thread::Semaphore;

   no warnings 'redefine';
   sub new { 
      my $class = shift;
      if (@_ && is_shared($_[0])) {
         return bless \$_[0], $class;
      } else {
         my $val : shared = @_ ? shift : 1;
         return bless \$val, $class;
      }
   }
}

my $line_semi_count : shared = 0;
my $line_semi = Thread::Semaphore->new($line_semi_count);

...
$line_semi->down(1);
...
$line_semi->up(1);