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/test/test_all.sh

@@ -0,0 +1,61 @@
+#!/usr/bin/env bash
+
+# do ldns tests
+cd test || { echo "Must be executed from srcdir"; exit -1; }
+. common.sh
+
+# find tpkg
+if [ -z "$TPKG" ] || [ ! -x "$TPKG" ]
+then
+        if [ -x tpkg/tpkg ]		; then TPKG="$(pwd)/tpkg/tpkg"
+        elif [ -x test/tpkg/tpkg ]	; then TPKG="$(pwd)/test/tpkg/tpkg"
+        elif command -v tpkg > /dev/null; then TPKG="$(command -v tpkg)"
+        else
+		TPKG=$1
+		if [ -z "$TPKG" ]
+		then
+			TPKG=$HOME/repos/tpkg/tpkg
+                	echo Did not find tpkg program!
+                	exit -1
+		fi
+        fi
+fi
+
+is_freebsd=$(uname -s 2>&1 | grep -i -c 'freebsd')
+test_tool_avail "dig"
+
+echo start the test at "$(date)" in "$(pwd)"
+[ "$1" = "clean" ] || [ "$2" = "clean" ] && $TPKG clean
+$TPKG -a ../.. fake 01-compile.tpkg
+
+# Works only on FreeBSD really
+if [[ "$is_freebsd" -eq 0 ]]; then
+    $TPKG -a ../.. fake 02-lint.tpkg
+fi
+
+$TPKG -a ../.. fake 07-compile-examples.tpkg
+$TPKG -a ../.. fake 16-compile-builddir.tpkg
+$TPKG -a ../.. fake 30-load-pyldns.tpkg
+$TPKG -a ../.. fake 31-load-pyldnsx.tpkg
+$TPKG -a ../.. fake 32-unbound-regression.tpkg
+$TPKG -a ../.. fake 999-compile-nossl.tpkg
+command -v indent || $TPKG -a ../.. fake codingstyle.tpkg
+grep -q '^#define HAVE_SSL ' ../ldns/config.h || (
+	$TPKG -a ../.. fake 19-keygen.tpkg
+	$TPKG -a ../.. fake 20-sign-zone.tpkg
+	$TPKG -a ../.. fake 25-ZONEMD.tpkg
+)
+
+failed=0
+for tests in *.tpkg
+do
+	COMMAND="$TPKG -a ../.. exe $(basename "$tests")"
+	echo "$COMMAND"
+	$COMMAND
+	if [ $? -ne 0 ]; then ((failed=failed+1)); fi
+done 
+echo finished the test at "$(date)" in "$(pwd)"
+$TPKG report
+cd ..
+
+exit $failed