libm: Add a proper sincos() implementation

Add a proper sincos() implementation that unifies the common
calculations for sin and cos instead of running them twice.

This should cause a speedup even in code not using that
(fairly uncommon) function because gcc can optimize separate
sin() and cos() calls into sincos() calls.

Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>

Change-Id: I644578ab443506c7404d2638d6d4917ff6c96f20
1 file changed