fix: populate ldns submodule and add autotools to LDNS build stage

- Re-cloned zonemaster-ldns with --recurse-submodules so the bundled
  ldns C library source (including Changelog and configure.ac) is present
- Added autoconf, automake, libtool to Dockerfile.backend ldns-build stage
  so libtoolize + autoreconf can generate ldns/configure during make

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

zonemaster-ldns/ldns/pcat/pcat-print.1

@@ -0,0 +1,64 @@
+'\" t
+.TH PCAT-PRINT 1 "08 Mar 2006" "pcat utils"
+.SH NAME
+pcat-print \- reformat hexadecimal packets back to dig-like syntax
+.SH SYNOPSIS
+.B pcat-printp
+[
+.IR \-h
+]
+.IR PCAT_STREAM
+
+.SH DESCRIPTION
+\fBpcat-print\fR reads in a pcat file and reformats the hexadecimal
+packets back into a dig-like syntax. If a packet cannot be transformed
+back into a sane syntax an error is emitted.
+
+This makes the manual inspection of the packets easier.
+
+.PP
+If no pcat file is given, standard input is read.
+
+.SH OPTIONS
+There are no options. Like \fBpcat-diff\fR this utility always does
+what you want.
+
+.SH OUTPUT FORMAT
+\fBpcat-print\fR will output records. 
+Each record consists of an index and then three packets.
+Each packet is separated by a line of '='s. All in all the output looks
+like:
+
+        ==========================
+        ==========================
+        Index: xxx:yyy
+        ==========================
+        query packet
+        ==========================
+        first answer/query packet
+        ==========================
+        second answer/query packet
+        ==========================
+.PP
+For the index: xxx:yyy. xxx is the query ID of the first answer/query and
+yyy is the query ID of the second one. These two IDs should match. The query
+ID of the query packet is also equal to xxx.
+
+.SH ALSO SEE
+Also see pcat(1) and pcat-diff(1).
+
+.SH AUTHOR
+Written by Miek Gieben for NLnet Labs.
+
+.SH REPORTING BUGS
+Report bugs to <dns-team@nlnetlabs.nl>.
+
+.SH COPYRIGHT
+Copyright (C) 2005, 2006 NLnet Labs. This is free software. There is NO
+warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
+PURPOSE.
+.PP
+Licensed under the BSD License. 
+
+
+