how-to modify perl @INC relatively to the executing script during compile time

#!/usr/bin/perl -wT

package isg_pub::load ;

   use strict ; use warnings ; use diagnostics;

   $|++;

   require Exporter ;

   our @ISA = qw(Exporter);

   our %EXPORT_TAGS = ( 'all' => [ qw() ] );

   our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } );

   our @EXPORT = qw() ;

   our $AUTOLOAD =();

   use utf8 ;

   use Carp ;

   use Cwd qw ( abs_path ) ;

   foreach (sort keys %ENV) {

      print "$_  =  $ENV{$_}\n";

   }

   BEGIN {

      $ENV{'PERL5LIB'} = '' ;

      my $my_inc_path = abs_path( $0 );

      $my_inc_path =~ m/^(.*)(\\|\/)(.*?)(\\|\/)(.*)/;

      $my_inc_path = $1;

      push ( @INC , "$my_inc_path" ) ;

      push ( @INC , "$my_inc_path/lib" ) ;

      $ENV{'PERL5LIB'} .= "$my_inc_path" ;

      $ENV{'PERL5LIB'} .= ":$my_inc_path" ;

   }

# ... some code ...

1;

__END__