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);
2f'>refs</a><a class='active' href='/guix/log/gnu/packages/animation.scm'>log</a><a href='/guix/tree/gnu/packages/animation.scm?id=92c4b7c0fd74b4e71ad70bd94211e4dba35a012f'>tree</a><a href='/guix/commit/gnu/packages/animation.scm?id=92c4b7c0fd74b4e71ad70bd94211e4dba35a012f'>commit</a><a href='/guix/diff/gnu/packages/animation.scm?id=92c4b7c0fd74b4e71ad70bd94211e4dba35a012f'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/packages/animation.scm'>
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<div class='path'>path: <a href='/guix/log/?id=92c4b7c0fd74b4e71ad70bd94211e4dba35a012f'>root</a>/<a href='/guix/log/gnu?id=92c4b7c0fd74b4e71ad70bd94211e4dba35a012f'>gnu</a>/<a href='/guix/log/gnu/packages?id=92c4b7c0fd74b4e71ad70bd94211e4dba35a012f'>packages</a>/<a href='/guix/log/gnu/packages/animation.scm?id=92c4b7c0fd74b4e71ad70bd94211e4dba35a012f'>animation.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/animation.scm?id=92c4b7c0fd74b4e71ad70bd94211e4dba35a012f&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2019-06-06 05:59:01 +0200'>2019-06-06</span></td><td><a href='/guix/commit/gnu/packages/animation.scm?id=9405f8b8a41898322b97d4abec216b9dcd9d6914'>gnu: pencil2d: Update to 0.6.4.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/animation.scm (pencil2d): Update to 0.6.4.
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2019-04-14 20:15:29 +0200'>2019-04-14</span></td><td><a href='/guix/commit/gnu/packages/animation.scm?id=05f6b03217bdb8d024b5d29b50fdec74413a312e'>gnu: synfig, synfigstudio: Update to 1.2.2.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/animation.scm (synfig-version): New variable.
(etl)[version]: Use it.
(synfig)[version]: Likewise.
[source]: Update to 1.2.2.
[native-inputs]: Add intltool.
(synfigstudio)[version]: Use SYNFIG-VERSION.
[source]: Update to 1.2.2.  Remove obsolete patch.
* gnu/packages/patches/synfigstudio-fix-ui-with-gtk3.patch: Delete file.
* gnu/local.mk (dist_patch_DATA): Remove it.
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2019-04-14 20:15:29 +0200'>2019-04-14</span></td><td><a href='/guix/commit/gnu/packages/animation.scm?id=36c8f1f1e629b0d1cd33647385e222880b6c3286'>gnu: etl: Update to 1.2.2.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/animation.scm (etl): Update to 1.2.2.
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2019-03-20 20:42:40 +0100'>2019-03-20</span></td><td><a href='/guix/commit/gnu/packages/animation.scm?id=c21242d920acf5023f674849a30a45c4e84fbc6e'>gnu: pencil2d: Update to 0.6.3.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/animation.scm (pencil2d): Update to 0.6.3.
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>