Fix Perl module Module::Pluggable such that it can find plugins that live in
symlinked directories.

Patch borrowed/adapted from Nixpkgs.

--- Module-Pluggable-5.2/lib/Module/Pluggable/Object.pm   2015-04-08 23:28:48.120164135 -0500
+++ Module-Pluggable-5.2/lib/Module/Pluggable/Object.pm   2015-04-08 23:30:27.032166704 -0500
@@ -164,7 +164,7 @@
         my $sp = catdir($dir, (split /::/, $searchpath));

         # if it doesn't exist or it's not a dir then skip it
-        next unless ( -e $sp && -d _ ); # Use the cached stat the second time
+        next unless ( -e $sp );

         my @files = $self->find_files($sp);

@@ -279,7 +279,7 @@
                              (my $path = $File::Find::name) =~ s#^\\./##;
                              push @files, $path;
                            }
-                      }, $search_path );
+                      }, "$search_path/." );
     }
     #chdir $cwd;
     return @files;</td><td class='sub right'></td></tr></table>
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<tr><td><span title='2020-10-03 00:04:43 +0200'>2020-10-03</span></td><td><a href='/guix/commit/gnu/packages/mes.scm?id=95b16cd886e0ba74feaf560199c69f2a6aec04de'>gnu: nyacc: Use versioned Guile site directory.</a><span class='msg-avail'>...<span class='msg-tooltip'>This is a follow-up to commit 4e896da45d7be42ff1ad0b2be741b168573e6f0e.

* gnu/packages/mes.scm (nyacc)[source]: Add snippet.
</span></span></td><td>Ricardo Wurmus</td></tr>
<tr><td><span title='2020-09-25 23:26:22 +0200'>2020-09-25</span></td><td><a href='/guix/commit/gnu/packages/mes.scm?id=4e896da45d7be42ff1ad0b2be741b168573e6f0e'>gnu: nyacc: Add 1.03.0.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/mes.scm (nyacc): Rename to...
(nyacc-0.99): ... this.
(nyacc): New variable.
(mes)[propagated-inputs]: Replace NYACC with NYACC-0.99.
(mes-rb5)[native-inputs]: Likewise.
* gnu/packages/commencement.scm (mes-boot)[native-inputs]: Likewise.
(tcc-boot0)[native-inputs]: Likewise.
</span></span></td><td>Ludovic Courtès</td></tr>