Update Gnus customizations

Use fancy unicode characters to show threading.

Use a line-spacing of 0.1 instead of 0.2 in summary buffers so the
unicode characters connect.

Start a new thread when the subject changes.

Fix some compilation warnings.

emacs/.emacs.d/init.el

@@ -944,7 +944,7 @@ If no direction is given, don't split."
   #'eshell-fringe-status-mode)
 
 (oni:add-hooks 'gnus-summary-mode-hook
-  #'oni:make-readable (lambda ()
+  (lambda ()
     (local-set-key (kbd "M-d") (lambda ()
                                  (interactive)
                                  (gnus-summary-delete-article)

emacs/.emacs.d/site-lisp/gnus-init.el

@@ -1,10 +1,12 @@
 (eval-when-compile
   (require 'gnus)
   (require 'gnus-start)
-  (require 'gnus-sum)
   (require 'gnus-art)
   (require 'gnus-msg))
 
+(require 'gnus-sum)
+(require 'nnfolder)
+
 (defvar gnus-tmp-from)
 
 (defvar oni:mail-adresses
@@ -38,8 +40,17 @@
 (defvar gnus-face-5 'font-lock-variable-name-face)
 (defvar gnus-face-6 'font-lock-constant-face)
 
+;;; Make threads in Gnus look awesome.
+(setq gnus-sum-thread-tree-false-root ""
+      gnus-sum-thread-tree-indent "  "
+      gnus-sum-thread-tree-leaf-with-other "├─"
+      gnus-sum-thread-tree-root ""
+      gnus-sum-thread-tree-single-indent ""
+      gnus-sum-thread-tree-single-leaf "└─"
+      gnus-sum-thread-tree-vertical "│ ")
+
 (setq gnus-group-line-format "%P    %(%C%) %B%60=%4y%-2M%S\n")
-(setq gnus-summary-line-format "%U%R%z%ua%I%(%*%[%5{%-23,23f%}%]%) %s\n")
+(setq gnus-summary-line-format "%U%R%z%ua%B%(%*%[%5{%-23,23f%}%]%) %s\n")
 (setq gnus-summary-mode-line-format "Gnus: %G %Z")
 (setq gnus-select-method
       '(nnmaildir "ryuslash"
@@ -91,3 +102,13 @@
 (add-hook 'gnus-group-mode-hook 'gnus-topic-mode)
 
 (setq message-kill-buffer-on-exit t)
+
+;;; Split threads on subject changes.
+(setq gnus-thread-ignore-subject nil)
+
+;;; Decrease line height in gnus summary buffers to make the unicode
+;;; characters connect.
+(add-hook 'gnus-summary-mode-hook (lambda () (setq line-spacing 0.1)) :append)
+
+(provide 'gnus-init)
+;;; gnus-init.el ends here