Packs everything into a single lib/ directory.

def make_lib(self, version):
        """
        Packs everything into a single lib/ directory.
        """
        if os.path.exists(POETRY_LIB_BACKUP):
            shutil.rmtree(POETRY_LIB_BACKUP)

        # Backup the current installation
        if os.path.exists(POETRY_LIB):
            shutil.copytree(POETRY_LIB, POETRY_LIB_BACKUP)
            shutil.rmtree(POETRY_LIB)

        try:
            self._make_lib(version)
        except Exception:
            if not os.path.exists(POETRY_LIB_BACKUP):
                raise

            shutil.copytree(POETRY_LIB_BACKUP, POETRY_LIB)
            shutil.rmtree(POETRY_LIB_BACKUP)

            raise
        finally:
            if os.path.exists(POETRY_LIB_BACKUP):
                shutil.rmtree(POETRY_LIB_BACKUP)