timsort
namespace gfx
I just realized that the namespace gfx has two million hits on GitHub alone: it is most likely a common abbreviation for "graphics" and it's used in big engines (it notably appears in the Fuchsia source code).
I'm not sure what to do about this. We could probably play it safe and use namespace timsort instead, which apparently doesn't exist. That would give a timsort::timsort(...) function, a timsort/timsort.hpp header to include and a timsort::timsort CMake target. It doesn't feel like the coolest solution, but it's probably pragmatic enough.
Not sure if the timsort namespace is a good idea. The namespace name clash is relatively benign. An entity other than namespace could be named timsort and that conflict would not compile... If you decide that such a clash is unlikely, then consider the timsort::sort and timsort::merge names rather than the repetitive timsort::timsort and timsort::timmerge.
To be honest I don't plan to change anything until someone complains that it breaks things in their code base, just letting the issue opened to let people know that we're aware of the potential issue.