mbrlen
size_t mbrlen(const char * __restrict, size_t, mbstate_t * __restrict);
PROTO_NORMAL(mbrlen);
DEF_STRONG(mbrlen);
nconv = mbrlen(p, MB_CUR_MAX, &mbs);
#define count_mbytes(buffer,length,state) mbrlen(buffer,length,&(state))
clen = mbrlen(optarg, MB_CUR_MAX, NULL);
clen = mbrlen(optarg + delim1len,
charlen = mbrlen(s + cptr, n, &mbs);