Add MANIFEST check to tests

MANIFEST.SKIP

@@ -78,3 +78,6 @@ t/po-files.t
 
 # Development mode aid for File::ShareDir
 ^lib/auto/share/dist/Zonemaster-CLI
+
+# Avoid MANIFEST test
+t/manifest.t

Makefile.PL

@@ -28,6 +28,8 @@ requires(
     'Zonemaster::Engine' => 6.000000,  # v6.0.0
 );
 
+test_requires      'Test::NoWarnings'        => 0;
+
 # Make all platforms include inc/Module/Install/External.pm
 requires_external_bin 'find';
 if ($^O eq "freebsd") {

t/manifest.t

@@ -0,0 +1,37 @@
+#!perl
+use v5.14.2;
+use strict;
+use warnings;
+use utf8;
+use Test::More tests => 2;
+use Test::NoWarnings;
+
+use File::Basename qw( dirname );
+
+chdir dirname( dirname( __FILE__ ) ) or BAIL_OUT( "chdir: $!" );
+
+my $makebin = 'make';
+
+sub make {
+    my @make_args = @_;
+
+    undef $ENV{MAKEFLAGS};
+
+    my $command = join( ' ', $makebin, '-s', @make_args );
+    my $output = `$command 2>&1`;
+
+    if ( $? == -1 ) {
+        BAIL_OUT( "failed to execute: $!" );
+    }
+    elsif ( $? & 127 ) {
+        BAIL_OUT( "child died with signal %d, %s coredump\n", ( $? & 127 ), ( $? & 128 ) ? 'with' : 'without' );
+    }
+
+    return $output, $? >> 8;
+}
+
+subtest "distcheck" => sub {
+    my ( $output, $status ) = make "distcheck";
+    is $status, 0,  $makebin . ' distcheck exits with value 0';
+    is $output, "", $makebin . ' distcheck gives empty output';
+};