It works perfectly, the library is built using all the sources. Even when defining INSTALL, all the properties of the targets (include files, config files, etc.) can be accessed and are installed correctly
The problem starts when I want to export a CMake file listing all the libraries which were defined by the individual modules (and are accessed by $<BUILD_INTERFACE:Module2_LIBRARIES>) since they know what they need (how they were configured).
When building a static library (which is shown here), I need to export a list of additional libraries necessary to link the Product1 correctly. But using $<BUILD_INTERFACE:Module_LIBRARIES> in the INSTALL() command does not work, neither works something like: