動かない原因がわからない

h.pl

use h1;
use h2;

use Data::Dumper;
print "h1::\n" . Dumper \%h1::;
print "h2::\n" . Dumper \%h2::;

h1sub1;
h2sub1;

h1.pm

package h1;

use Exporter 'import';

our @EXPORT = qw(
  h1sub1
  h1sub2
);

use h2;

sub h1sub1 {
  h2sub2();
}

sub h1sub2 {
  print("h1sub2");
}

1;

h2.pm

package h2;

use Exporter 'import';

our @EXPORT = qw(
  h2sub1
  h2sub2
);

use h1;

sub h2sub1 {
  h1sub2();
}

sub h2sub2 {
  print("h2sub2");
}

1;

result

h1::
$VAR1 = {
          'h1sub1' => *h1::h1sub1,
          'h2sub2' => *h1::h2sub2,
          'EXPORT' => *h1::EXPORT,
          'h1sub2' => *h1::h1sub2,
          'BEGIN' => *h1::BEGIN,
          'h2sub1' => *h1::h2sub1,
          'import' => *h1::import
        };
h2::
$VAR1 = {
          'import' => *h2::import,
          'h2sub1' => *h2::h2sub1,
          'EXPORT' => *h2::EXPORT,
          'h1sub2' => *h2::h1sub2,
          'BEGIN' => *h2::BEGIN,
          'h2sub2' => *h2::h2sub2
        };
Undefined subroutine &h2::h1sub2 called at h2.pm line 13.
h2sub2

あらためてドキュメントをよむと、BEGINで@exportのあたりをBEGINで実行すればよいようだった。
http://perldoc.perl.org/Exporter.html#Playing-Safe
Exporter::Easy使うのがお手軽っぽいので、それでやる方向で。