Declare nonguix as a channel dependency in .guix-channel

metznet/machines/otto.scm uses (nongnu packages mozilla), but guix pull
builds this channel's own modules in isolation unless a dependency is
declared, so that module came up as "no code for module" too. Declare
nonguix using the same introduction already used in channels.d/nonguix.scm.

.guix-channel

@@ -1,2 +1,15 @@
+;; metznet/machines/otto.scm uses (nongnu packages mozilla), so guix pull
+;; needs to know nonguix is a build-time dependency -- otherwise it tries
+;; to compile/load this channel's own modules in isolation and fails with
+;; "no code for module (nongnu packages mozilla))".
 (channel
-  (version 0))
+  (version 0)
+  (dependencies
+   (channel
+    (name nonguix)
+    (url "https://gitlab.com/nonguix/nonguix")
+    (introduction
+     (channel-introduction
+      (version 0)
+      (commit "897c1a470da759236cc11798f4e0a5f7d4d59fbc")
+      (signer "2A39 3FFF 68F4 EF7A 3D29 12AF 6F51 20A0 22FB B2D5"))))))

channels.d/metznet.scm

@@ -1,5 +1,6 @@
-;; See channels.scm for why this needs an explicit import.
-(use-modules (guix channels))
+;; See channels.scm for why this needs a real define-module.
+(define-module (channels.d metznet)
+  #:use-module (guix channels))
 
 (channel
         (name 'metznet-channel)

channels.d/nonguix.scm

@@ -1,5 +1,6 @@
-;; See channels.scm for why this needs an explicit import.
-(use-modules (guix channels))
+;; See channels.scm for why this needs a real define-module.
+(define-module (channels.d nonguix)
+  #:use-module (guix channels))
 
 (channel
   (name 'nonguix)

channels.d/nonguixgames.scm

@@ -1,5 +1,6 @@
-;; See channels.scm for why this needs an explicit import.
-(use-modules (guix channels))
+;; See channels.scm for why this needs a real define-module.
+(define-module (channels.d nonguixgames)
+  #:use-module (guix channels))
 
 (channel
         (name 'guix-gaming-games)

channels.scm

@@ -1,18 +1,27 @@
 ;; channels.scm -- reads the channels.d dir to get a list of channel objects
+;;
+;; `guix pull` also compiles every .scm file under this channel's own
+;; checkout as an ordinary package module (see standard-module-derivation)
+;; and then loads each by its path-derived module name (e.g. this file as
+;; (channels)) to build the package cache -- so, like metznet/machines/*.scm,
+;; this needs a real define-module matching its path, not just a bare
+;; script relying on guix pull -C's implicit (guix channels) import.
+(define-module (channels)
+  #:use-module (gnu)
+  #:use-module (guix channels)
+  #:use-module ((ice-9 ftw) #:select (scandir)))
 
-;; guix pull -C pre-imports (guix channels) into the file's environment
-;; (see load-channels/make-user-module in guix/scripts/pull.scm), which is
-;; why this worked without an explicit import. But `guix pull` also
-;; compiles every .scm file under this channel's own checkout as an
-;; ordinary package module (see standard-module-derivation), and that
-;; environment does NOT pre-import it -- so `channel` (a macro from (guix
-;; channels), used in channels.d/*.scm) and %default-channels come up
-;; unbound there unless imported explicitly.
-(use-modules (gnu) (guix channels) ((ice-9 ftw) #:select (scandir)))
+;; ./channels.d only resolves when the process's CWD happens to be this
+;; file's own directory, which isn't true once guix pull loads this as a
+;; plain module (e.g. from the store) to build its package cache -- anchor
+;; to this file's own location instead.
+(define here (dirname (current-filename)))
+
+(define channels-directory (string-append here "/channels.d"))
 
 (define channel-files
-  (scandir "./channels.d"
+  (scandir channels-directory
     (lambda (file)
       (string-suffix? ".scm" file))))
 
-(append (map (lambda (file) (load (string-append "./channels.d/" file))) channel-files) %default-channels)
+(append (map (lambda (file) (load (string-append channels-directory "/" file))) channel-files) %default-channels)