Creating a python package (deb/rpm) from cmake

As mentionned in my other solution, the ugly part is dealing with absolute path in cmake install() commands. I was able to refactor the code to avoid usage of absolute path in install(). I simply changed the installation into:

install(
  # trailing slash is important:
  DIRECTORY ${SETUP_OUTPUT}/
  # "." syntax is a reliable mechanism, see:
  # https://gitlab.kitware.com/cmake/cmake/-/issues/22616
  DESTINATION "."
  COMPONENT python)

And then one simply needs to:

set(CMAKE_INSTALL_PREFIX "/")
set(CPACK_PACKAGING_INSTALL_PREFIX "/")
include(CPack)

At this point all install path now need to include explicitely /usr since we've cleared the value for CMAKE_INSTALL_PREFIX.

The above has been tested for deb and rpm packages. CPACK_BINARY_TGZ does properly run with the above solution:

• https://gitlab.kitware.com/cmake/cmake/-/issues/22925