[BUG] CMake error when using PyBind11 and range-v3 as submodules

[est77]

The PR that introduced this error is #2370

add_library cannot create target "headers" because another target with the
same name already exists. The existing target is a custom target created
in source directory "extern/range-v3". See
documentation for policy CMP0002 for more details.

Would it be possible to rename the target to something less generic to avoid this issue?
(I opened another issue in range-v3 repo).

Thanks.

[henryiii]

I was a little worried about making that "headers" due to this issue. I have an idea, actually...

[henryiii]

The only non-imported target is headers, so working around this is pretty easy. Here's the idea:

Rename headers to pybind11_headers. For add_directory, have an alias pybind11::headers. For config mode, also alias pybind11::pybind11_headers to pybind11::headers.

The other alternative would be to name it something different if this is a subdirectory, but that can be troublesome.