OP_FAIL_POS      1521 regcomp.c          r = add_opcode(reg, OP_FAIL_POS);
OP_FAIL_POS      6234 regcomp.c        { OP_FAIL_POS,             "fail-pos",             ARG_NON },
OP_FAIL_POS      2991 regexec.c          CASE(OP_FAIL_POS)  MOP_IN(OP_FAIL_POS);