produce a usable installation even after a build failure
CMake, by default, requires that all build artifacts have been correctly produced when installing.
It's possible to tell CMake that a build artifact is
OPTIONAL, but it's not easy nor correct to change all invocations of the
install command to use the
OPTIONAL flag (we risk to deploy incomplete builds without noticing).
What we can do is to patch the CMake generated
cmake_install.cmake files in the nightlies so that we can effectively turn all build artifacts to
OPTIONAL in the special case of the nightly builds.