I am now working on my c++ project. I would like to use CMake targeting multiple platforms in a single build. From the post here
How to make CMake targeting multiple platforms in a single build
It mentioned that we can automate this by having an enclosing build script which invokes CMake once for each target platform and performs several out-of-source builds to distinct binary directories. The enclosing script could also be written in CMake(ExternalProject). I have no idea how to write this automation in Cmake ExternalProject. Could anyone suggest me an idea or give me an example on it?