mpz_ndiv_qr wanted

[paul zimmermann]

       Dear GMP developers,

after having written ten times (if not hundred) a function that computes an
integer quotient and remainder with rounding to nearest, I believe this could
be a nice addition to GMP, and useful to other users too.

I propose:

 -- Function: void mpz_ndiv_qr (mpz_t Q, mpz_t R, const mpz_t N, const mpz_t D)

    Divide N by D, forming a quotient Q and/or remainder R such that
    N = Q*D + R. The quotient Q is rounded to nearest, i.e., either
    |R| < D/2, or if |R| = D/2, then Q is even (can occur only for even D).

and of course the corresponding mpz_ndiv_q and mpz_ndiv_r functions.
(The tie-breaking rule for the case |R| = D/2 comes from IEEE 754.)

Best regards,
Paul