This happens with 6.42 < ExtUtils::MakeMaker < 6.57_02

WARNING: AUTHOR takes a string/number not a ARRAY reference.
         Please inform the author.
Checking if your kit is complete...
Looks good
only nested arrays of non-refs are supported at /usr/share/perl5/ExtUtils/MakeMaker.pm line 684

--- Parse-RecDescent/Makefile.PL
+++ Parse-RecDescent/Makefile.PL
@@ -4,10 +4,7 @@
 
 WriteMakefile(
     NAME             => 'Parse::RecDescent',
-    AUTHOR           => [
-        'Damian Conway <DCONWAY@CPAN.org>',
-        'Jeremy T. Braun <JTBRAUN@CPAN.org>',
-    ],
+    AUTHOR           => 'Damian Conway <DCONWAY@CPAN.org>, Jeremy T. Braun <JTBRAUN@CPAN.org>',
     VERSION_FROM     => 'lib/Parse/RecDescent.pm',
     ABSTRACT_FROM    => 'lib/Parse/RecDescent.pm',
     PL_FILES         => {},