std::optional<T>::emplace() without a value is broken on clang++ with gnu libstdc++. this workarounds the bug by using the assignment operator instead. https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101227 Bug: None Change-Id: I6fd096ff4d632259e6eab776e318c1d7b15e4bd5 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/365400 Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org> Reviewed-by: Harald Alvestrand <hta@webrtc.org> Cr-Commit-Position: refs/heads/main@{#43229}