SHF_DYNAMIC
if (!buf && (sflags & SHF_WR) && (sflags & SHF_DYNAMIC)) {
if (!(flags & EB_GROW) || !(shf->flags & SHF_DYNAMIC) ||
shf_sopen(NULL, 0, SHF_WR|SHF_DYNAMIC, &shf);
shf_sopen(s, n, SHF_WR | (s ? 0 : SHF_DYNAMIC), &shf);
shf_sopen(NULL, 32, SHF_WR | SHF_DYNAMIC, &shf);