# File lib/phusion_passenger/platform_info/apache.rb, line 167
        def self.httpd_default_config_file(options = nil)
                if options
                        info = httpd_V(options)
                else
                        info = httpd_V
                end
                if info
                        info =~ /-D SERVER_CONFIG_FILE="(.+)"$/
                        filename = $1
                        if filename =~ /\A\//
                                return filename
                        else
                                # Not an absolute path. Infer from default root.
                                if root = httpd_default_root(options)
                                        return "#{root}/#{filename}"
                                else
                                        return nil
                                end
                        end
                else
                        return nil
                end
        end