TSAN logs as requested by @YannickJadoul here:

#2746 (comment)

Using master b7dfe5c
+ #2409
+ #2746 (YannickJadoul@727b3ae)
+ 2 additional minor local patches.

test -c dbg --config=tsan (Google-internal toolchain)

Failing tests:

• test_gil_scoped.py [EDIT: see PR Add PYBIND11_SIMPLE_GIL_MANAGEMENT option (cmake, C++ define) #4216]
• test_iostream.py [EDIT: see PR Adding iostream.h thread-safety documentation. #2995]:

  pybind11/tests/test_iostream.cpp

  Line 43 in d587a2f

  t_ = new std::thread(std::move(thread_f));