uboot: (firmwareOdroidC2/C4) don't invoke patch tool, use patches = [] instead

https://github.com/NixOS/nixpkgs/blob/master/pkgs/stdenv/generic/setup.sh#L948
this can do it nicely.

Signed-off-by: Anton Arapov <anton@deadbeef.mx>

nixos/doc/manual/configuration/user-mgmt.chapter.md

@@ -0,0 +1,92 @@
+# User Management {#sec-user-management}
+
+NixOS supports both declarative and imperative styles of user
+management. In the declarative style, users are specified in
+`configuration.nix`. For instance, the following states that a user
+account named `alice` shall exist:
+
+```nix
+users.users.alice = {
+  isNormalUser = true;
+  home = "/home/alice";
+  description = "Alice Foobar";
+  extraGroups = [ "wheel" "networkmanager" ];
+  openssh.authorizedKeys.keys = [ "ssh-dss AAAAB3Nza... alice@foobar" ];
+};
+```
+
+Note that `alice` is a member of the `wheel` and `networkmanager`
+groups, which allows her to use `sudo` to execute commands as `root` and
+to configure the network, respectively. Also note the SSH public key
+that allows remote logins with the corresponding private key. Users
+created in this way do not have a password by default, so they cannot
+log in via mechanisms that require a password. However, you can use the
+`passwd` program to set a password, which is retained across invocations
+of `nixos-rebuild`.
+
+If you set [](#opt-users.mutableUsers) to
+false, then the contents of `/etc/passwd` and `/etc/group` will be congruent
+to your NixOS configuration. For instance, if you remove a user from
+[](#opt-users.users) and run nixos-rebuild, the user
+account will cease to exist. Also, imperative commands for managing users and
+groups, such as useradd, are no longer available. Passwords may still be
+assigned by setting the user\'s
+[hashedPassword](#opt-users.users._name_.hashedPassword) option. A
+hashed password can be generated using `mkpasswd -m
+  sha-512`.
+
+A user ID (uid) is assigned automatically. You can also specify a uid
+manually by adding
+
+```nix
+uid = 1000;
+```
+
+to the user specification.
+
+Groups can be specified similarly. The following states that a group
+named `students` shall exist:
+
+```nix
+users.groups.students.gid = 1000;
+```
+
+As with users, the group ID (gid) is optional and will be assigned
+automatically if it's missing.
+
+In the imperative style, users and groups are managed by commands such
+as `useradd`, `groupmod` and so on. For instance, to create a user
+account named `alice`:
+
+```ShellSession
+# useradd -m alice
+```
+
+To make all nix tools available to this new user use \`su - USER\` which
+opens a login shell (==shell that loads the profile) for given user.
+This will create the \~/.nix-defexpr symlink. So run:
+
+```ShellSession
+# su - alice -c "true"
+```
+
+The flag `-m` causes the creation of a home directory for the new user,
+which is generally what you want. The user does not have an initial
+password and therefore cannot log in. A password can be set using the
+`passwd` utility:
+
+```ShellSession
+# passwd alice
+Enter new UNIX password: ***
+Retype new UNIX password: ***
+```
+
+A user can be deleted using `userdel`:
+
+```ShellSession
+# userdel -r alice
+```
+
+The flag `-r` deletes the user's home directory. Accounts can be
+modified using `usermod`. Unix groups can be managed using `groupadd`,
+`groupmod` and `groupdel`.