make asdf follow the XDG spec

To make asdf roughly follow the XDG spec:

• (I'm assuming that you want to use default XDG dirs, replace ~/.local/share with XDG_DATA and ~/.local/config with XDG_CONFIG as necessary if you don't)
• install it to ~/.local/share/asdf:
  • git clone https://github.com/asdf-vm/asdf.git ~/.local/share/asdf --branch v0.11.3
• set a whole bunch of environment variables. Here's the section from my ~/.bashrc:

if [[ -d $HOME/.local/share/asdf ]]; then
    # I really wish asdf supported XDG_CONFIG:
    # https://github.com/asdf-vm/asdf/issues/687
    #
    # so let's set a bunch of variables that let us pretend it does
    export ASDF_DIR="$HOME/.local/share/asdf"
    export ASDF_DATA_DIR="$HOME/.local/share/asdf"

    . "$ASDF_DIR/asdf.sh"
    . "$ASDF_DIR/completions/asdf.bash"

    # https://asdf-vm.com/manage/configuration.html#asdfrc
    export ASDF_CONFIG_FILE="$HOME/.config/asdf/asdfrc"

    # https://github.com/asdf-vm/asdf-nodejs#default-npm-packages
    export ASDF_NPM_DEFAULT_PACKAGES_FILE="$HOME/.config/asdf/default-npm-packages"

    # https://github.com/asdf-community/asdf-python#default-python-packages
    export ASDF_PYTHON_DEFAULT_PACKAGES_FILE="$HOME/.config/asdf/default-python-packages"
fi

Once you have those variables set, you should have asdf config in ~/.config/asdf and asdf binaries and package installs in ~/.local/share/asdf.

If you already have asdf installed to the default location of ~/.asdf, you can move that directory into ~/.config/asdf and run asdf reshim.

• unfortunately the python builds embed the directory for the location of shared modules, I had to blow away and re-install python to move it successfully

this issue tracks asdf support of the XDG spec