They are hacks that paper over the lack of good package management. Plus they are too much extra work, and OS-specific. No build system integrates with them as far as I know.
I think what people want is something like go, where you add a single line to your code and it magically downloads and compiles the referenced library. C++ doesn't have anything like that (and I doubt it ever will to be honest).
I think what people want is something like go, where you add a single line to your code and it magically downloads and compiles the referenced library. C++ doesn't have anything like that (and I doubt it ever will to be honest).