Fix various Perl packages

Perl 5.20 removed some modules, in particular Module::Pluggable. So
now other modules need to get it from CPAN.

http://hydra.nixos.org/build/17450281

maintainers/scripts/nix-generate-from-cpan.nix

@@ -3,7 +3,7 @@
 stdenv.mkDerivation {
   name = "nix-generate-from-cpan-1";
 
-  buildInputs = [ makeWrapper perl perlPackages.YAMLLibYAML perlPackages.JSON ];
+  buildInputs = [ makeWrapper perl perlPackages.YAMLLibYAML perlPackages.JSON perlPackages.CPANPLUS ];
 
   unpackPhase = "true";
   buildPhase = "true";
@@ -19,4 +19,4 @@ stdenv.mkDerivation {
     maintainers = [ stdenv.lib.maintainers.eelco ];
     description = "Utility to generate a Nix expression for a Perl package from CPAN";
   };
-}
+}

maintainers/scripts/nix-generate-from-cpan.pl

@@ -100,7 +100,7 @@ sub get_deps {
     foreach my $n (keys %{$deps}) {
         next if $n eq "perl";
         # Hacky way to figure out if this module is part of Perl.
-        if ($n !~ /^JSON/ && $n !~ /^YAML/) {
+        if ($n !~ /^JSON/ && $n !~ /^YAML/ && $n !~ /^Module::Pluggable/) {
             eval "use $n;";
             if (!$@) {
                 print STDERR "skipping Perl-builtin module $n\n";