Sinc(x) is a simple function used in communications. boost
happens to use it for quaternion math. The implementation is
simple, however it looks fun to re-use the boost function
even if just to say we are using quaternion math somewhere ;).

The performance difference is not likely to be huge but JIC,
set up a specific Boost math policy to limit type promotion
with it's corresponding impact.
(cherry picked from commit d1f61b3f)

Conflicts:
	vcl/inc/vcl/bitmap.hxx

Change-Id: I5f01db1688eedee25a2943ca3aa6e957b400c759