How to create a cmake header-only library that depends on external header files?

Question

I have a project with the following file structure:

project
 |
 |-------> lib1
 |           |----> lib1.h
 |
 |-------> lib2
 |           |---->          


        

Answer 1

I've used an empty _only_for_compiling_the_lib.cpp file as the simplest and fastest workaround, but clearly the above solution is strongly advised.

I simply wasn't aware of INTERFACE keyword.