- 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

Fix a bug where the wrong argument was passed to SET_FLOAT_WORD().
This bug results in a type mismatch that happens to be harmless
because of the way SET_FLOAT_WORD() works.

Submitted by: bde

s/rcsid/__FBSDID/

Implement nexttowardf. This is used on both platforms with 11-bit
exponents and platforms with 15-bit exponents for long doubles.