Let's say you need zip lib functionality in your project. If it will be available as set of .h files you would include it by one line `#include zip.h` in your .c file.

But libzip is made of .c files. How you would include it in your multiplatform project ? Visual Studio, XCode, etc...

In general it would be great if C has `#include source "some.c"` feature.

So you would add single file zip-lib.c that will contain `#include source ...` references to all needed .c files.

But C/C++ has no modules as other languages so we need palliatives like make files, etc.