The problem with this scheme is that adding a dependency to a header now breaks source compatibility (even if nothing new needs to be linked in and a piece of a

The problem with this scheme is that adding a dependency to a header now breaks source compatibility (even if nothing new needs to be linked in and a piece of a library just needs to pull in a different piece of itself or even of libc). It’s pretty and clean, but you need an environment that’s friendly to crosscutting changes to handle source-compat breakage. (Such as, yes, a dependency-tree leaf like an end-user application, or a monolithic tree like a traditional Unix.)