* guix/ui.scm (program-name, guix-warning-port): New variables.
(warning): New macro.
(guix-main): Parametrize PROGRAM-NAME.
* guix/scripts/build.scm, guix/scripts/download.scm,
guix/scripts/gc.scm, guix/scripts/package.scm: Adjust to use `leave'
and `warning' consistently.
* guix/gnu-maintenance.scm (http-fetch): Error out when DATA is #f.
* guix/scripts/package.scm (check-package-freshness): Wrap
`gnu-package?' call in `false-if-exception'.
Reported by Cyril Roelandt <tipecaml@gmail.com>.
* guix/store.scm (&nix-connection-error): New condition type.
(open-connection): Translate `system-error' during the `connect' call
into `&nix-connection-error'.
* guix/ui.scm (call-with-error-handling): Add case for `nix-connection-error?'.
* guix/scripts/package.scm (guix-package): Move `open-connection' call
within `with-error-handling'.
* guix/scripts/pull.scm (guix-pull): Likewise.
* guix/scripts/download.scm (guix-download): Move body within
`with-error-handling'.
* guix/gnu-maintenance.scm (gnu-package?): New procedure.
* guix/scripts/package.scm (waiting): New macro.
(check-package-freshness): New procedure.
(guix-package)[process-actions]: Use it.
* doc/guix.texi (Invoking guix package): Mention the feature.
* guix/scripts/package.scm (read/eval-package-expression): New
procedure.
(show-help): Add `-e'.
(%options): Likewise.
(guix-package)[process-actions]: Handle ('install . p) pairs, where P
is a package.
* tests/guix-package.sh: Add `boot_make_drv'. Use `-i $boot_make_drv'
once, and then use `-e $boot_make'.
* doc/guix.texi (Invoking guix package): Document `-e'.
Ludovic Courtès