my $config_prefix = $Config{installprefixexp} || $Config{installprefix} ||
$Config{prefixexp} || $Config{prefix};
-is( $mm->{PREFIX}, $config_prefix, 'PREFIX' );
+is( $mm->{PERLPREFIX}, '$(DESTDIR)'.$config_prefix, 'PERLPREFIX' );
is( !!$mm->{PERL_CORE}, !!$ENV{PERL_CORE}, 'PERL_CORE' );