Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

I'm happy to finally commit stephen@'s implementations of cacos,
cacosh, casin, casinh, catan, and catanh. Thanks to stephen@ and bde@
for working on these.

Submitted by: stephen@
Reviewed by: bde

Add c{cos,sin,tan}{,h}{,f} functions. This is joint work with
bde and kargl.