I'm still confused as to why linux requires linking against TBB for multithreading, thus breaking cmake configs without if(linux) for tbb. That stuff should be included by default without any effort by the developer.
Using pthread in C, for example, TBB is not required.
Not sure about C11 threads, but I have always thought that GLIBC just uses pthread under the hood.
C++26 will get another similar dependency, because BLAS algorithms are going to be added, but apparently the expectation is to build on top of C/Fortran BLAS battle tested implementations.