New emacs/ediff module

Ediff config was moved out of core. Also includes evil compatibility
(mvoed out of feature/evil) & wconf save/restore.

modules/emacs/ediff/config.el

@@ -0,0 +1,25 @@
+;;; emacs/ediff/config.el -*- lexical-binding: t; -*-
+
+;; `ediff'
+(setq ediff-diff-options "-w" ; turn off whitespace checking
+      ediff-split-window-function #'split-window-horizontally
+      ediff-window-setup-function #'ediff-setup-windows-plain)
+
+;; Restore window config after quitting ediff
+(defvar +ediff--saved-wconf nil)
+
+(defun +ediff|save-wconf ()
+  (setq +ediff--saved-wconf (current-window-configuration)))
+(defun +ediff|restore-wconf ()
+  (set-window-configuration +ediff--saved-wconf))
+(add-hook 'ediff-before-setup-hook #'+ediff|save-wconf)
+(add-hook! '(ediff-quit-hook ediff-suspend-hook) #'+ediff|restore-wconf 'append)
+
+
+;;
+;; Plugins
+;;
+
+(def-package! evil-ediff
+  :when (featurep! :feature evil)
+  :after ediff)

modules/emacs/ediff/packages.el

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+;; -*- no-byte-compile: t; -*-
+;;; emacs/ediff/packages.el
+
+(when (featurep! :feature evil)
+  (package! evil-ediff))