perl-net-dns-resolver-programmable used the undocumented and internal
method Net::DNS::rcodesbyname [0], and that interface is no longer
exposed.

This patch, copied from [1], makes the program check for the existence
of the method before trying to use it.

[0]
<https://rt.cpan.org/Public/Bug/Display.html?id=95901>

[1]
<https://rt.cpan.org/Public/Bug/Display.html?id=95901#txn-1575108>

diff --git a/lib/Net/DNS/Resolver/Programmable.pm b/lib/Net/DNS/Resolver/Programmable.pm
index 1af72ce..e09a2f0 100644
--- a/lib/Net/DNS/Resolver/Programmable.pm
+++ b/lib/Net/DNS/Resolver/Programmable.pm
@@ -203,8 +203,10 @@ sub send {
     if (defined(my $resolver_code = $self->{resolver_code})) {
         ($result, $aa, @answer_rrs) = $resolver_code->($domain, $rr_type, $class);
     }
-    
-    if (not defined($result) or defined($Net::DNS::rcodesbyname{$result})) {
+
+    if (not defined($result)
+         or defined($Net::DNS::Parameters::rcodebyname{$result})
+         or defined($Net::DNS::rcodesbyname{$result})) {
         # Valid RCODE, return a packet:
         
         $aa     = TRUE      if not defined($aa);
eb'>refs</a><a class='active' href='/guix/log/gnu/packages/libdaemon.scm'>log</a><a href='/guix/tree/gnu/packages/libdaemon.scm?id=7d990e775e76c0a898c7d4b53691d1932fc0e6eb'>tree</a><a href='/guix/commit/gnu/packages/libdaemon.scm?id=7d990e775e76c0a898c7d4b53691d1932fc0e6eb'>commit</a><a href='/guix/diff/gnu/packages/libdaemon.scm?id=7d990e775e76c0a898c7d4b53691d1932fc0e6eb'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/packages/libdaemon.scm'>
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<div class='path'>path: <a href='/guix/log/?id=7d990e775e76c0a898c7d4b53691d1932fc0e6eb'>root</a>/<a href='/guix/log/gnu?id=7d990e775e76c0a898c7d4b53691d1932fc0e6eb'>gnu</a>/<a href='/guix/log/gnu/packages?id=7d990e775e76c0a898c7d4b53691d1932fc0e6eb'>packages</a>/<a href='/guix/log/gnu/packages/libdaemon.scm?id=7d990e775e76c0a898c7d4b53691d1932fc0e6eb'>libdaemon.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/packages/libdaemon.scm?id=7d990e775e76c0a898c7d4b53691d1932fc0e6eb&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-09-20 11:15:08 +0000'>2021-09-20</span></td><td><a href='/guix/commit/gnu/packages/libdaemon.scm?id=35e1a572f6424c4d9bd2679590be14d664dd2121'>gnu: libdaemon: Support cross-compilation to aarch64-linux-gnu.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/libdaemon.scm
  (libdaemon)[native-inputs]: Add "config" when cross-compiling for
  aarch64.
  (libdaemon)[arguments]&lt;#:phases&gt;{update-config.sub}: When cross-compiling
  for aarch64, update the "config.sub" script.
</span></span></td><td>Maxime Devos</td></tr>
<tr><td><span title='2020-04-11 19:22:26 +0200'>2020-04-11</span></td><td><a href='/guix/commit/gnu/packages/libdaemon.scm?id=5ea5d0512f912375358c339f81334454b03ef5a3'>gnu: libdaemon: Cross-build with --localstatedir=/var.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/libdaemon.scm (libdaemon)[arguments]: Add
"--localstatedir=/var" when (%current-target-system) is true.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-04-11 19:22:26 +0200'>2020-04-11</span></td><td><a href='/guix/commit/gnu/packages/libdaemon.scm?id=a16022a7b889cefc86cb368c3475a7d0dd2edfb6'>gnu: libdaemon: Allow cross-compilation.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/libdaemon.scm (libdaemon)[arguments]: New field.
</span></span></td><td>Ludovic Courtès</td></tr>