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 class='sub right'></td></tr></table>
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<div class='path'>path: <a href='/guix/log/?id=1623e6023b9b2cd3dbcb663404067717ba6445f1'>root</a>/<a href='/guix/log/build-aux?id=1623e6023b9b2cd3dbcb663404067717ba6445f1'>build-aux</a>/<a href='/guix/log/build-aux/cuirass?id=1623e6023b9b2cd3dbcb663404067717ba6445f1'>cuirass</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/build-aux/cuirass?id=1623e6023b9b2cd3dbcb663404067717ba6445f1&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-03-10 08:49:48 +0100'>2021-03-10</span></td><td><a href='/guix/commit/build-aux/cuirass?id=76bea3f8bcd951ded88dfb7f8cad5bc3e5a1701f'>ci: Remove hydra support.</a><span class='msg-avail'>...<span class='msg-tooltip'>This removes hydra support to use Cuirass as the only continuous integration
system.

* build-aux/hydra/gnu-system.scm: Remove it.
* build-aux/hydra/guix-modular.scm: Ditto.
* build-aux/hydra/guix.scm: Ditto.
* build-aux/cuirass/hydra-to-cuirass.scm: Ditto.
* Makefile.am (EXTRA_DIST): Update it.
(hydra-jobs.scm): Remove it.
(cuirass-jobs.scm): Update it.
* build-aux/hydra/evaluate.scm: Move it to ...
* build-aux/cuirass/evaluate.scm: ... here.
* build-aux/cuirass/guix-modular.scm: Remove it.
* build-aux/cuirass/gnu-system.scm: Ditto.
* guix/packages.scm (%hydra-supported-systems): Rename it to ...
(%cuirass-supported-systems): ... this variable.
* build-aux/check-final-inputs-self-contained: Adapt it.
* etc/release-manifest.scm: Ditto.
* gnu/ci.scm (package-&gt;alist): Remove it.
(derivation-&gt;job): New procedure.
(package-job, package-cross-job, cross-jobs, image-jobs, system-test-jobs,
tarball-jobs): Use it.
(guix-jobs): New procedure.
(hydra-jobs): Rename it to ...
(cuirass-jobs): ... this procedure.
</span></span></td><td>Mathieu Othacehe</td></tr>
<tr><td><span title='2020-10-04 14:04:14 +0200'>2020-10-04</span></td><td><a href='/guix/commit/build-aux/cuirass?id=fdbf8a7a75e9d63957ea6d8a63181aa131edeaea'>cuirass: Add hurd-manifest.</a><span class='msg-avail'>...<span class='msg-tooltip'>* build-aux/cuirass/hurd-manifest.scm: New file.
</span></span></td><td>Jan (janneke) Nieuwenhuizen</td></tr>