BEGIN {
    package MY;

    use File::Spec::Functions qw( catdir catfile );

    sub init_PM {
        my $self = shift;

        $self->SUPER::init_PM(@_);

        my $src_base = 'bin';
        my $dst_base = '$(INSTALLSCRIPT)';

        for ('script.pl', ...) {
            my $src = catfile(              $src_base, $_);
            my $dst = join('$(DIRFILESEP)', $dst_base, $_);
            $self->{PM}{$src} = $dst;
        }
    }
}