No. Actually, it's easy. Just check for directory or use a fallback. For example here's how you'd do this in bash:

    export CONFIG_DIR="${XDG_CONFIG_HOME:-$HOME/.config}"
    export CACHE_DIR="${XDG_CACHE_HOME:-$HOME/.cache}"
    ...

XDG_*_DIRS are a bit more complicated, but nothing that can't be solved with a simple for-loop in any modern programming language.