gpt_add_hdr
if (gpt_add_hdr(gpt, MAP_TYPE_PRI_GPT_HDR, 1) == -1)
if (gpt_add_hdr(gpt, MAP_TYPE_SEC_GPT_HDR, last) == -1)
int gpt_add_hdr(gpt_t, int, off_t);
if (gpt_add_hdr(gpt, type, last) == -1)
if (gpt_add_hdr(gpt, MAP_TYPE_SEC_GPT_HDR, newloc) == -1)