Merge pull request #5131 from shuujii/remove-unused-constant-in-lib-mruby-build-command.rb

Remove unused constant in `lib/mruby/build/command.rb`

lib/mruby/build/command.rb

@@ -32,8 +32,6 @@ module MRuby
       end
     end
 
-    NotFoundCommands = {}
-
     private
     def _run(options, params={})
       sh "#{build.filename(command)} #{options % params}"