[CMake] How does CPACK decide what goes into release packages?

[kent williams]

It's mentioned in passing on the CMake Wiki, which is all the
documentation I've found for CPack. Namely

"Internally, CPack will use CMake's install mechanism to automatically
populate the package."

but when I add

include(CPack)

and then run

make package

It generates empty install packages.

The only target (for now) that needs to go into the package is a
single statically linked executable, which is referenced with a cmake
install command:

INSTALL(TARGETS BRAINSFit DESTINATION bin)

I don't understand how you tell CPack what to install, and I've
re-read the Wiki page several times.  Am I just stupid?