def command?(command)
      MakeMakefile::Logging.instance_variable_set :@logfile, File::NULL
      MakeMakefile::Logging.quiet = true
      MakeMakefile.find_executable command.to_s
    end
def command?(command)
      MakeMakefile::Logging.instance_variable_set :@logfile, File::NULL
      MakeMakefile::Logging.quiet = true
      MakeMakefile.find_executable command.to_s
    end
Checks if command exists.
 @param command [String] command name to check
 @return [String, nil] full path to command or nil if not found