conf->ap_document_root = SvPV_nolen(new_root);
conf->ap_document_root = apr_pstrdup(r->pool, SvPV_nolen(new_root));
const char *mpxs_Apache__RequestRec_document_root(pTHX_ request_rec *r,                                                  SV *new_root){    const char *retval = ap_document_root(r);    if (new_root) {        core_server_config *conf;        MP_CROAK_IF_THREADS_STARTED("setting $r->document_root");        conf = ap_get_module_config(r->server->module_config,                                     &core_module);        conf->ap_document_root = SvPV_nolen(new_root);    }    return retval;}