[CMake] static library from several subdirectories

[Verweij, Arjen]

Hi,

For a legacy FORTRAN project, I'm looking for a cmake-way to create a static library from several subdirectories. The current solution is using a custom POST_BUILD step with ar and ranlib, but the resulting archive is not known to cmake and can't be used to link to the main.

As an alternative we've tried to propagate the list of archives using PARENT_SCOPE, but this seems like a hack as well. Is there a clean way to go about it?

Regards,
Arjen