PR 92463 - Cleanups due to minimum MPFR version bump to 3.1.0

PR 92463 - Cleanups due to minimum MPFR version bump to 3.1.0

        PR middle-end/92463
        * configure.ac: Use MPFR_RNDN instead of GMP's MP_RNDN.
        * configure: Regenerate

        gcc/
        PR middle-end/92463
        * builtins.c (do_mpfr_ckconv, do_mpc_ckconv, do_mpfr_remquo,
        do_mpfr_lgamma_r, do_mpc_arg2): Use MPFR_RNDx instead of GMP_RNDx,
        mpfr_rnd_t instead of mp_rnd_t.
        * fold-const-call.c (do_mpfr_ckconv, do_mpfr_arg1, do_mpfr_sincos,
        do_mpfr_arg2, do_mpfr_arg3, do_mpc_arg1, do_mpc_arg2): Likewise.
        * gimple-ssa-sprintf.c (format_floating_max, format_floating):
        Use mpfr_exp_t instead of mp_exp_t.
        * real.c (real_from_string, dconst_e_ptr, dconst_sqrt2_ptr): Use
        MPFR_RNDx instead of GMP_RNDx.
        * realmpfr.c (real_from_mpfr, mpfr_from_real): Use mpfr_rnd_t and
        mpfr_exp_t instead mp_rnd_t and mp_exp_t, respectively.
        * realmpfr.h (real_from_mpfr, mpfr_from_real): Use mpfr_rnd_t instead
        of mp_rnd_t and remove MPFR_RNDx poisoning.
        * ubsan.c (ubsan_instrument_float_cast): MPFR_RNDx instead of GMP_RNDx.

        fortran/
        PR middle-end/92463
        * arith.c (gfc_check_real_range): Replace mp_exp_t by mpfr_exp_t.

From-SVN: r278761