- Copy stable/10@285827 to releng/10.2 in preparation for 10.2-RC1
builds.
- Update newvers.sh to reflect RC1.
- Update __FreeBSD_version to reflect 10.2.
- Update default pkg(8) configuration to use the quarterly branch.[1]

Discussed with: re, portmgr [1]
Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r257770 r257818 r257823 r260066 r260067 r260089 r260145 r268587 r268588
r268589 r268590 r268593 r268597 r269758 r270845 r270847 r270893 r270932
r270947 r271147

Merge libm work by kargl, bde and das from the past few months.
Besides optimisations and small bug fixes this includes new implementations
for C99 functions expl, coshl, sinhl, tanhl, erfl and erfcl.

Approved by: re (kib)

* Makefile:
. Add s_erfl.c to building libm.
. Add MLINKS for erfl.3 and erfcl.3.

* Symbol.map:
. Move erfl and erfcl to their proper location.

* ld128/s_erfl.c:
. Implementations of erfl and erfcl in the IEEE 754 128-bit format.

* ld80/s_erfl.c:
. Implementations of erfl and erfcl in the Intel 80-bit format.

* man/erf.3:
. Document the new functions.
. While here, remove an incomplete sentence.

* src/imprecise.c:
. Remove the stupidity of mapping erfl and erfcl to erf and erfc.

* src/math.h:
. Move the declarations of erfl and erfcl to their proper place.

* src/s_erf.c:
. For architectures where double and long double are the same
floating point format, use weak references to map erfl to
erf and ercl to erfc.

Reviewed by: bde (many earlier versions)