if (NOT USE_UPSTREAM_LIBPQXX)
    # If we use the system pqxx library, we have to check for libpq.
    # This check is done by the CMakeLists.txt of the libpqxx project otherwise
    find_package(PQXX REQUIRED)
    ...
else (NOT USE_UPSTREAM_LIBPQXX)
    set(SKIP_BUILD_TEST TRUE)
    include(FetchContent)
    FetchContent_Declare(
            libpqxx
            GIT_REPOSITORY https://github.com/jtv/libpqxx.git
            GIT_TAG 7.6.0
    )
    ...
endif (NOT USE_UPSTREAM_LIBPQXX)