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;></table>
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<div class='path'>path: <a href='/guix/log/?id=42be8fa560a7554ac35801b46c3a0a007fd742ce'>root</a>/<a href='/guix/log/m4?id=42be8fa560a7554ac35801b46c3a0a007fd742ce'>m4</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/m4?id=42be8fa560a7554ac35801b46c3a0a007fd742ce&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-11-07 18:07:11 +0200'>2023-11-07</span></td><td><a href='/guix/commit/m4?id=220759226e93d76d8d80058f69f9d8b29714bbde'>build: Fix spelling in m4 macros.</a><span class='msg-avail'>...<span class='msg-tooltip'>* m4/guix.m4 (GUIX_CHECK_GUILE_SSH): Fix spelling of parameter.
(GUIX_CHECK_FILE_NAME_LIMITS): Fix spelling of maximum.

Change-Id: I93c80441393622a4bc06daa475eee13874cca527
</span></span></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2023-03-16 12:37:03 +0100'>2023-03-16</span></td><td><a href='/guix/commit/m4?id=8e3dfb3d6dfc0f19bd9a9f9b163f0f3d7dccc865'>build: Correct guix_system on musl libc distros.</a><span class='msg-avail'>...<span class='msg-tooltip'>* m4/guix.m4 (GUIX_SYSTEM_TYPE): Add linux-musl* case. This prevents
the macro from mis-parsing the host OS, which causes breakage when
building from source.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Antero Mejr</td></tr>