Note that END blocks are executed in the reverse order they are "registered". If you want or need your END block to run last, you need to put it before any use directives (though should be safe to put it after strict and warnings).

use strict;
use warnings;

my $exit_normally = 0;
sub exit_handler;
END { exit_handler; }

# other use directives

sub exit_handler { ... }

...

$exit_normally = 1;
__END__
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