> the alternative means hooking up the library’s module system to yours
What "module system"? The alternative would be one .c file and one .h file. It's negligible effort to add these to any project that already has more than one .c file.
I meant build system, such as cmake. I assume the alternative to a single-header library would be lots of .c and .h files, and something to build them into a dynamically-linked library. The alternative, just dumping them into your project, means that once you get into .c files you typically have to start enumerating those somewhere in your own build system, rather than just including them from one of your own headers.
