build-system/linux-module: Support module source versioning.

* guix/build-system/linux-module.scm (make-linux-module-builder)
[native-inputs]: Add linux.
[arguments]<#:phases>[install]: Install "System.map" and "Module.symvers".
* guix/build/linux-module-build-system.scm (configure): Delete procedure.
(%standard-phases): Delete "configure" phase.

guix/build-system/linux-module.scm

@@ -63,6 +63,9 @@
   (package
     (inherit linux)
     (name (string-append (package-name linux) "-module-builder"))
+    (native-inputs
+     `(("linux" ,linux)
+       ,@(package-native-inputs linux)))
     (arguments
      (substitute-keyword-arguments (package-arguments linux)
       ((#:phases phases)
@@ -72,11 +75,17 @@
               (invoke "make" "modules_prepare")))
           (delete 'strip) ; faster.
           (replace 'install
-            (lambda* (#:key outputs #:allow-other-keys)
+            (lambda* (#:key inputs outputs #:allow-other-keys)
               (let* ((out (assoc-ref outputs "out"))
                      (out-lib-build (string-append out "/lib/modules/build")))
                 ; TODO: Only preserve the minimum, i.e. [Kbuild], Kconfig, scripts, include, ".config".
                 (copy-recursively "." out-lib-build)
+                (let* ((linux (assoc-ref inputs "linux")))
+                  (install-file (string-append linux "/System.map")
+                                out-lib-build)
+                  (let ((source (string-append linux "/Module.symvers")))
+                    (if (file-exists? source)
+                        (install-file source out-lib-build))))
                 #t)))))))))
 
 (define* (lower name

guix/build/linux-module-build-system.scm

@@ -32,10 +32,6 @@
 ;;
 ;; Code:
 
-;; TODO: It might make sense to provide "Module.symvers" in the future.
-(define* (configure #:key inputs #:allow-other-keys)
-  #t)
-
 (define* (build #:key inputs make-flags #:allow-other-keys)
   (apply invoke "make" "-C"
          (string-append (assoc-ref inputs "linux-module-builder")
@@ -64,7 +60,7 @@
 
 (define %standard-phases
   (modify-phases gnu:%standard-phases
-    (replace 'configure configure)
+    (delete 'configure)
     (replace 'build build)
     (replace 'install install)))