* s_erf.c:
  . Use integer literal constants instead of double literal constants.

* s_erff.c:
  . Use integer literal constants instead of casting double literal
    constants to float.
  . Update the threshold values from those carried over from erf() to
    values appropriate for float.
  . New sets of polynomial coefficients for the rational approximations.
    These coefficients have little, but positive, effect on the maximum
    error in ULP in the four intervals, but do improve the overall
    speed of execution.
  . Remove redundant GET_FLOAT_WORD(ix,x) as hx already contained the
    contents that is packed into ix.
  . Update the mask that is used to zero-out lower-order bits in x in
    the intervals [1.25, 2.857143] and [2.857143, 12].  In tests on
    amd64, this change improves the maximum error in ULP from 6.27739
    and 63.8095 to 3.16774 and 2.92095 on these intervals for erffc().

Reviewed by:	bde
If a drive returns ASC/ASCQ 0x04,0x11 "Logical unit not ready,
notify (enable spinup) required", instead of doing the normal
retries, poll for a change in status.

We will poll every half second for a minute for the status to
change.

Hitachi drives (and likely other SAS drives) return that ASC/ASCQ
when they are waiting to spin up.  What it means is that they are
waiting for the SAS expander to send them the SAS
NOTIFY (ENABLE SPINUP) primitive.

That primitive is the mechanism expanders/enclosures use to
sequence drive spinup to avoid overloading power supplies.

Sponsored by:	Spectra Logic
MFC after:	3 days