Adding upstream version 0.6.0.

Signed-off-by: Daniel Baumann <daniel@debian.org>

doc/refcheck.pl

@@ -0,0 +1,27 @@
+#!/usr/bin/perl
+
+use warnings;
+use strict;
+
+my @files = @ARGV;
+
+my $h;
+
+foreach my $file (@files) {
+    $h->{$file} = 1;
+}
+
+foreach my $file (@files) {
+    open(my $fh, "<", $file) or die "cannot open < $file: $!";
+    while (<$fh>) {
+        chomp;
+        if ($_ =~ /\.Xr ((ck|CK)_[a-zA-Z_]+) ([0-9])/) {
+	    my $name = $1;
+	    my $section = $3;
+	    if (!$h->{$name}) {
+		print STDERR "$file: ref to missing ${name}($section)\n";
+	    }
+        }
+    }
+    close($fh) or die("cannot close $file: $!");
+}