- 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

Add a support macro to convert the 5-bit packed register field of
a floating point instruction into a 6-bit register number for
double and quad arguments.
Make use of the new INSFPdq_RN macro where apporpriate; this
is required for correctly handling the "high" fp registers
(>= %f32).
Fix a number of bugs related to the handling of the high registers
which were caused by using __fpu_[gs]etreg() where __fpu_[gs]etreg64()
should be used (the former can only access the low, single-precision,
registers).

Submitted by: tmm

Emulate ldq and stq (load/store long double) instructions. GCC has started
using these to load long doubles, but they aren't implemented in hardware
on (at least) UltraSPARC I and II machines.
Emulate popc in the user trap handler as well.
Re-arrange slightly to make support functions more accessible.

Reviewed by: tmm