- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

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

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

ieeefp.h is only needed on i386 class hardware.

Submitted by: bde
Approved by: das (pre-approved)

Whitespace.

Submitted by: bde
Approved by: das (pre-approved)

Replace code that toggles between 53 and 64 bits on i386
class hardware with the ENTERI and RETURNI macros, which
are now available in math_private.h.

Suggested by: bde
Approved by: das (mentor)

Take two. Add the missing file that should have been committed
with r219571 and re-enable building of cbrtl.

Implement the long double version for the cube root function, cbrtl.
The algorithm uses Newton's iterations with a crude estimate of the
cube root to converge to a result.

Reviewed by: bde
Approved by: das