- DENSURE((d), (s)->len + 1); \
- memcpy((d)->buf + (d)->len, (s)->buf, (s)->len); \
- (d)->len += (s)->len; \
- (d)->buf[(d)->len] = 0; \
+ dstr *_d = (d); \
+ const dstr *_s = (s); \
+ DENSURE(_d, _s->len + 1); \
+ memcpy(_d->buf + _d->len, _s->buf, _s->len); \
+ _d->len += _s->len; \
+ _d->buf[_d->len] = 0; \