- log2 is not available on Android before API 18.
- Android doesn't have 'round' on the std:: namespace when using g++.
Co-authored-by: Thiago Marcos P. Santos <thiago@mapbox.com>
GLIBC 2.27 added new versioned symbols of powf and logf, while the double versions of pow and log remained stable.
Prefer the double version to avoid introducing a dependency on a newer version of GLIBC than strictly necessary.
See https://lists.gnu.org/archive/html/info-gnu/2018-02/msg00000.html