Since commit f31e6deb this drags in
ridiculous amounts of boost headers, for probably negigible improvemnts
of sin(x)/x for tiny x values.

The compile time impact was not negligible, moving this nonsense to its
own header removes 1.79 GB of preprocessor input from a full build.

Change-Id: Ic41b2210eac8b130726610f2dbdbb449379225d1