Allow enumeration field types

Rakefile

@@ -25,11 +25,10 @@ task default: :boot
 
 desc 'Final stage'
 task boot: "build/valid/#{STAGES.last}/cl"
-task boot: "build/valid/#{STAGES.last}/cl.s"
 task boot: "boot/#{STAGES.last}/cl.elna" do |t|
   groupped = t.prerequisites.group_by { |stage| File.extname stage }.transform_values(&:first)
   exe = groupped['']
-  expected = groupped['.s']
+  expected = groupped[''] + '.s'
   source = groupped['.elna']
 
   cat_arguments = ['cat', source]
@@ -46,6 +45,10 @@ task :convert do
   end
 end
 
+file "build/valid/#{STAGES.last}/cl" => 'build/build.ninja' do |t|
+  sh 'ninja', '-f', t.prerequisites.first
+end
+
 file 'build/build.ninja' => ['build'] do |t|
   File.open t.name, 'w' do |f|
     f << <<~NINJA