One wonders whether PIC is needed at all... CMake already defaults on PIC for shared libraries.

https://cmake.org/cmake/help/v4.1/prop_tgt/POSITION_INDEPENDENT_CODE.html

Could be PIC for static lib right? Whatever .a that got linked into .so in downstream needs to be built with PIC.

But if you need PIC in the static library, why won't you set CMAKE_POSITION_INDEPENDENT_CODE?

I don't know why this line is there in the first place.

This PR is only to make it "less wrong".
Whether it can be totally removed is another story.

I'll merge because you are improving things. I'll open an issue.

Running tests first.

Although I do want to point out it is not always possible to set a single CMAKE_POSITION_INDEPENDENT_CODE globally, because that can also affect other sub-project built in that run.
Ideally, as long as the performance is good, we should just set PIC for all builds of simdjson, so that downstream user do not need to worry about how they build simdjson.