sincos?

[enh]

i'm a recent lurker on this list; i've inherited Android's C library, and
among other things i'm trying to track FreeBSD's lib/msun much more closely
than we have traditionally.

i was just reminded of the existence of a change submitted to us (Android)
a while back that adds a sincos/sincosf implementation cobbled together
from your s_sin.c/s_sinf.c and s_cos.c/s_cosf.c implementations:
https://android-review.googlesource.com/#/c/47585/<https://android-review.googlesource.com/#/c/47585/1>

the submitter (Intel) rightly points out that at the moment GCC carefully
optimizes paired sin/cos calls into a sincos call which we deoptimize back
into separate sin/cos calls. i personally don't want to take on maintenance
of this, but i would be happy to include you guys' sincos implementation if
you had one. is there a reason you don't have one? what's the clang story
with this optimization (it's my understanding you're moving away from GCC
in favor of clang)?

 --elliott