Find and return the target with the specified id, treated
            relative to self.

def find_really(self, id):
        """ Find and return the target with the specified id, treated
            relative to self.
        """
        assert isinstance(id, basestring)

        result = None
        current_location = self.get ('location')

        __re_split_project_target = re.compile (r'(.*)//(.*)')
        split = __re_split_project_target.match (id)

        project_part = None
        target_part = None

        if split:
            project_part = split.group(1)
            target_part = split.group(2)
            if not target_part:
                get_manager().errors()(
                    'Project ID, "{}", is not a valid target reference. There should '
                    'be either a target name after the "//" or the "//" should be removed '
                    'from the target reference.'
                    .format(id)
                )


        project_registry = self.project_.manager ().projects ()

        extra_error_message = ''
        if project_part:
            # There's explicit project part in id. Looks up the
            # project and pass the request to it.
            pm = project_registry.find (project_part, current_location)

            if pm:
                project_target = project_registry.target (pm)
                result = project_target.find (target_part, no_error=1)

            else:
                extra_error_message = "error: could not find project '$(project_part)'"

        else:
            # Interpret target-name as name of main target
            # Need to do this before checking for file. Consider this:
            #
            #  exe test : test.cpp ;
            #  install s : test : <location>. ;
            #
            # After first build we'll have target 'test' in Jamfile and file
            # 'test' on the disk. We need target to override the file.

            result = None
            if self.has_main_target(id):
                result = self.main_target(id)

            if not result:
                result = FileReference (self.manager_, id, self.project_)
                if not result.exists ():
                    # File actually does not exist.
                    # Reset 'target' so that an error is issued.
                    result = None


            if not result:
                # Interpret id as project-id
                project_module = project_registry.find (id, current_location)
                if project_module:
                    result = project_registry.target (project_module)

        return result