New comment by Johnnynator on void-packages repository

https://github.com/void-linux/void-packages/pull/18135#issuecomment-572695507

Comment:
> also i think `threading=multi` is actually not default and we've been building boost wrong all along

Why that? I think multi is what we want. Since threadsafe code should work everywhere albeit with a performance drawback. The alternative would be to just build boost 4 times instead of only 2 times right now (`static/single`, `static/multi`, `dynamic/single`, `dynamic/multi`), but I doubt that it would be worth it.

> threading
>
>    Allowed values: single, multi
>
>    Controls if the project should be built in multi-threaded mode. This feature does not necessary change code generation in the compiler, but it causes the compiler to link to additional or different runtime libraries, and define additional preprocessor symbols (for example, _MT on Windows and _REENTRANT on Linux). How those symbols affect the compiled code depends on the code itself.