libstdc++: do not use std::logf or std::powf In libstdc++ there is no implementation of std::logf or std::powf, so they must be replaced with calls to std::log and std::pow, and use static_cast for using the right overload. Bug: chromium:957519 Change-Id: I3c94502c006db200148060c1d30e0dd28b8a30d0 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4352890 Reviewed-by: Amirali Abdolrashidi <abdolrashidi@google.com> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>