+ * `--linkfarm[=no|shallow|git|full]`: Override nailing-cargo's
+ approach to out-of-tree builds. Normally nailing-cargo chooses
+ automatically whether to make a linkfarm, and precisely what kind
+ of linkfarm, based on the cargo subcommand. The linkfarm styles
+ are:
+
+ * `no`: Do not make a linkfarm; pass a `--manifest-path` option
+ pointing to the actual source directory. This is the default
+ for most cargo commands.
+
+ * `shallow`: Symlink top-level objects in the source directory,
+ including whole subdirectories. This the default when
+ nailing-cargo thinks cargo is going to update `Cargo.lock`.
+
+ * `git`: Make a deep linkfarm, with subdirectories. Symlink
+ those objects tracked by git. This is the default for
+ `cargo publish`.
+
+ * `full`: Make a deep linkfarm and symlink every nondirectory found
+ in the source tree. This will including all sorts of junk,
+ including for example editor backup files.
+
+ Whenever nailing-cargo linkfarms, old symlinks pointing back to
+ the source tree are deleted. In each case, `Cargo.lock` is not
+ symlinked, but copied. If nailing-cargo expects cargo to update
+ `Cargo.lock`, it will copy it back to the source tree afterwards.
+ Just `--linkfarm` is the same as `--linkfarm=git`.
+
+ * `--edit | --edit-sources | -E`: Permits the cargo command to edit
+ sources in the source tree. This is achieved by *copying* the
+ entire source tree (all files tracked by git) into the destination
+ directory, and then copying back all changed files. *Only git
+ tracked filles* can be edited by the cargo command; edits to
+ other files, and creation of new files, will be ignored.
+
+ When this option is repeated (**`-EE`**), the cargo subcommand can
+ create new files including dotfiles (but nothing in the toplevel
+ `target` and nothing called `.git`). (This also enables
+ `--preclean=src` by default.)
+
+ If you are running out of tree builds for privsep reasons, you
+ should use git to review the edits made by the cargo command and
+ either stage and commit them, or reject them.
+
+ This option is overridden by a subsequent `--linkfarm` options.
+
+ `-E` or `-f` is needed for `nailing-cargo fmt`. `-EE` or `-f` is
+ needed for `nailing-cargo init`. (`-E` is never the default.)
+
+ * `--just-linkfarm[=shallow|git|full]`: Make the out-of-tree
+ linkfarm as if for `--cargo-lock-update`, but do not actually run
+ any command, nor try to copy back a a generated `Cargo.lock`.
+ Forces `--keep-linkfarm` (even if the contrary is also specified).
+
+ With a linkfarming mode, overrides (and is overridden by)
+ `--linkfarm=`. Without a linkfarming mode, and without
+ `--linkfarm`, the default is `shallow`.