Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Add assembly versions of remquol() and remainderl().

Hook up sqrtl() to the build.

Implement rintl(), nearbyintl(), lrintl(), and llrintl().
Thanks to bde@ for feedback and testing of rintl().

Add logbl(3) to libm.

Removed the optimized asm versions of scalb() and scalbf(). These
functions are only for compatibility with obsolete standards. They
shouldn't be used, so they shouldn't be optimized. Use the generic
versions instead.

This fixes scalbf() as a side effect. The optimized asm version left
garbage on the FP stack. I fixed the corresponding bug in the optimized
asm scalb() and scalbn() in 1996. NetBSD fixed it in scalb(), scalbn()
and scalbnf() in 1999 but missed fixing it in scalbf(). Then in 2005
the bug was reimplemented in FreeBSD by importing NetBSD's scalbf().

The generic versions have slightly different error handling:
- the asm versions blindly round the second parameter to a (floating
point) integer and proceed, while the generic versions return NaN
if this rounding changes the value. POSIX permits both behaviours
(these functions are XSI extensions and the behaviour for a bogus
non-integral second parameter is unspecified). Apart from this
and the bug in scalbf(), the behaviour of the generic versions seems
to be identical. (I only exhusatively tested
generic_scalbf(1.0F, anyfloat) == asm_scalb(1.0F, anyfloat). This
covers many representative corner cases involving NaNs and Infs but
doesn't test exception flags. The brokenness of scalbf() showed up
as weird behaviour after testing just 7 integer cases sequentially.)

Add symbol versioning to libm.

More optimized math functions.

Implement and document remquo() and remquof().

- Define the LDBL_PREC to be the number of significant bits in a long
double's mantissa.
- Add an assembly version of scalbnl.

Remove the i387 versions of atan(), atan2(), and atan2f().
They are slower than the MI routines on modern hardware,
except for degenerate cases such as the Pentium 4.

PR: 67469

Remove i387 versions of asin() and acos(). Although the hardware
instruction was faster on the 486, it's slower than our MD version on
modern processors.

Determined by: bde
PR: 67469

Remove the float versions of the i387 trig functions obtained from
NetBSD. They're buggy, giving particularly for inputs larger in
magnitude than 2**63.

Noticed by: bde
PR: 67469

Move machine-dependent crud to its own makefile.