* real.h (struct real_value): Add signalling.
        (EXP_BITS): Decrement.
        * real.c (get_canonical_qnan): Don't set MSB-1.
        (get_canonical_snan): Likewise.  Set signalling.
        (real_identical): Compare signalling.
        (round_for_format): Remove force-one-bit on code.
        (real_nan): Likewise.  Set signalling.
        (encode_ieee_single): Add force-one-bit code; honor signalling.
        (encode_ieee_double, encode_ieee_extended, encode_ieee_quad): Likewise.
        (decode_ieee_single): Set signalling.
        (decode_ieee_double, decode_ieee_extended, decode_ieee_quad): Likewise.

From-SVN: r64935