RcppSpdlog bundles spdlog, a wonderful header-only C++ logging library with all the bells and whistles you would want that was written by Gabi Melman, and also includes fmt by Victor Zverovich. No R package-side changes were needed or made.
The (minimal) NEWS entry for this release follows.
Changes in RcppSpdlog version 0.0.6 (2021-07-21)
- Upgraded to upstream release spdlog 1.9.0
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