* etc/completion/bash/guix (_guix_complete_available_package): Cache the list of available packages in '_guix_available_packages' and use it. (_guix_complete): Cache the list of subcommands in '_guix_subcommands' and use it.
* etc/completion/bash/guix (_guix_complete_option): Change grep regexp to match options that don't have a short option name.
* etc/completion/bash/guix: New file. * Makefile.am (dist_bashcompletion_DATA): New variable. * configure.ac: Add --with-bash-completion-dir.