This might help.

use strict;
use warnings;

package PACKAGEA::PACKAGEB;

our @test = qw(a b c);
our $test = 'def';
our %tset = ('foo' => 'bar');
*PI = \'3.14';
our $PI;

print(@test, $/);
print($test, $/);
print(%tset, $/);
print($PI, $/);

package main;
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my $src_pkg_name = 'PACKAGEA::PACKAGEB';
my $dst_pkg_name = __PACKAGE__;

{
   no strict 'refs';
   
   foreach (keys(%$src_pkg_name)) {
      my $sym_name = $_;
      my $src_sym_ref = "$src_pkg_name::$sym_name";
      my $dst_sym_ref = "$dst_pkg_name::$sym_name";
      my $ref;
      $ref = *$src_sym_ref{SCALAR}; *$dst_sym_ref = $ref if $ref;
      $ref = *$src_sym_ref{ARRAY }; *$dst_sym_ref = $ref if $ref;
      $ref = *$src_sym_ref{HASH  }; *$dst_sym_ref = $ref if $ref;
      $ref = *$src_sym_ref{CODE  }; *$dst_sym_ref = $ref if $ref;
   }
}
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print(@test, $/);
print($test, $/);
print(%tset, $/);
print($PI, $/);
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Update: Oops! I had forgotten to test whether this imports functions -- which would be the most important here!! -- and it doesn't. I'm not sure how to fix ,and I can't look further into it at his moment.