Add a Net::DNS prereq for digdelv, fetchlimit, rpzrecurse, and zero

tests to avoid failed tests when Net::DNS is not present.

(cherry picked from commit 8b1b809ab4)

bin/tests/system/digdelv/prereq.sh

@@ -0,0 +1,21 @@
+#!/bin/sh
+#
+# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#
+# See the COPYRIGHT file distributed with this work for additional
+# information regarding copyright ownership.
+
+SYSTEMTESTTOP=..
+. $SYSTEMTESTTOP/conf.sh
+
+if $PERL -e 'use Net::DNS;' 2>/dev/null
+then
+    :
+else
+    echo "I:This test requires the Net::DNS library." >&2
+    exit 1
+fi

bin/tests/system/fetchlimit/prereq.sh

@@ -0,0 +1,21 @@
+#!/bin/sh
+#
+# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#
+# See the COPYRIGHT file distributed with this work for additional
+# information regarding copyright ownership.
+
+SYSTEMTESTTOP=..
+. $SYSTEMTESTTOP/conf.sh
+
+if $PERL -e 'use Net::DNS;' 2>/dev/null
+then
+    :
+else
+    echo "I:This test requires the Net::DNS library." >&2
+    exit 1
+fi

bin/tests/system/rpzrecurse/prereq.sh

@@ -21,4 +21,12 @@ if [ $ret != 0 ]; then
     exit 1
 fi
 
-exec $SHELL ../testcrypto.sh
+$SHELL ../testcrypto.sh || exit 255
+
+if $PERL -e 'use Net::DNS;' 2>/dev/null
+then
+    :
+else
+    echo "I:This test requires the Net::DNS library." >&2
+    exit 1
+fi

bin/tests/system/zero/prereq.sh

@@ -0,0 +1,21 @@
+#!/bin/sh
+#
+# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#
+# See the COPYRIGHT file distributed with this work for additional
+# information regarding copyright ownership.
+
+SYSTEMTESTTOP=..
+. $SYSTEMTESTTOP/conf.sh
+
+if $PERL -e 'use Net::DNS;' 2>/dev/null
+then
+    :
+else
+    echo "I:This test requires the Net::DNS library." >&2
+    exit 1
+fi