emacs: Add 'guix-build-log-find-file'.

* emacs/guix-build-log.el (guix-build-log-find-file): New procedure.
* emacs/guix-command.el (guix-run-view-build-log): Use it.

emacs/guix-build-log.el

@@ -24,6 +24,8 @@
 
 ;;; Code:
 
+(require 'guix-utils)
+
 (defgroup guix-build-log nil
   "Settings for `guix-build-log-mode'."
   :group 'guix)
@@ -359,6 +361,11 @@ programmatically using hooks:
   (when guix-build-log-minor-mode-activate
     (guix-build-log-minor-mode)))
 
+(defun guix-build-log-find-file (file-or-url)
+  "Open FILE-OR-URL in `guix-build-log-mode'."
+  (guix-find-file-or-url file-or-url)
+  (guix-build-log-mode))
+
 ;;;###autoload
 (add-to-list 'auto-mode-alist
              ;; Regexp for log files (usually placed in /var/log/guix/...)

emacs/guix-command.el

@@ -65,6 +65,7 @@
 (require 'guix-help-vars)
 (require 'guix-read)
 (require 'guix-base)
+(require 'guix-build-log)
 (require 'guix-guile)
 (require 'guix-external)
 
@@ -692,8 +693,7 @@ open the log file(s)."
          (output (guix-command-output args))
          (files  (split-string output "\n" t)))
     (dolist (file files)
-      (guix-find-file-or-url file)
-      (guix-build-log-mode))))
+      (guix-build-log-find-file file))))
 
 (defun guix-run-view-graph (args)
   "Run 'guix ARGS ...' graph command, make the image and open it."