create Makefile.PL in filegatherer phase

This allows other plugins to not just see that this file exists (at early
phases such as file munging, and generate files accordingly -- e.g.
[InstallGuide]), but allow other plugins to add content earlier (e.g.
Devel::CheckLib). The template will be evaluated at the normal time, once the
prereq list is finalized.

This change mirrors that in rjbs/Dist-Zilla#229, and live independently of
that, but must release first.

Author: karenetheridge

Changes

@@ -1,6 +1,8 @@
 Revision history for {{ $dist->name }}
 
 {{$NEXT}}
+    - create Makefile.PL at filegatherer phase, to allow other plugins to see
+      the file earlier
 
 0.22      2014-07-29 04:51:13Z
     - fix for Dist::Zilla::Plugin::MakeMaker 5.020 dropping a default required

lib/Dist/Zilla/Plugin/MakeMaker/Awesome.pm

@@ -8,8 +8,11 @@ use MooseX::Types::Stringlike 'Stringlike';
 use Moose::Autobox;
 use namespace::autoclean;
 use CPAN::Meta::Requirements 2.121; # requirements_for_module
+use List::Util 'first';
 
 extends 'Dist::Zilla::Plugin::MakeMaker' => { -version => 5.001 };
+# avoid wiping out the method modifications to dump_config done by superclass
+with 'Dist::Zilla::Role::FileGatherer' => { -excludes => 'dump_config' };
 
 sub mvp_multivalue_args { qw(WriteMakefile_arg_strs test_files exe_files) }
 
@@ -253,7 +256,22 @@ sub register_prereqs {
     return {};
 }
 
-sub setup_installer {
+sub gather_files
+{
+    my $self = shift;
+
+    require Dist::Zilla::File::InMemory;
+    my $file = Dist::Zilla::File::InMemory->new({
+        name    => 'Makefile.PL',
+        content => $self->MakeFile_PL_template,     # template evaluated later
+    });
+
+    $self->add_file($file);
+    return;
+}
+
+sub setup_installer
+{
     my $self = shift;
 
     ## Sanity checks
@@ -262,8 +280,12 @@ sub setup_installer {
 
     my $perl_prereq = $self->delete_WriteMakefile_arg('MIN_PERL_VERSION');
 
+    # file was already created; find it and fill in the content
+    my $file = first { $_->name eq 'Makefile.PL' } @{$self->zilla->files};
+    $self->log_debug([ 'updating contents of Makefile.PL in memory' ]);
+
     my $content = $self->fill_in_string(
-        $self->MakeFile_PL_template,
+        $file->content,
         {
             dist              => \($self->zilla),
             plugin            => \$self,
@@ -275,13 +297,7 @@ sub setup_installer {
             extra_args        => \($self->WriteMakefile_arg_strs),
         },
     );
-
-    my $file = Dist::Zilla::File::InMemory->new({
-        name    => 'Makefile.PL',
-        content => $content,
-    });
-
-    $self->add_file($file);
+    $file->content($content);
     return;
 }
 
@@ -508,6 +524,8 @@ Defaults to using data from C<:ExecDir> plugins.
 
 =head3 register_prereqs
 
+=head3 gather_files
+
 =head3 setup_installer
 
 =for stopwords dirs