Move startup optimizations into init.el

Doesn't really belong in core.el and only applies to interactive
sessions.

init.el

@@ -27,7 +27,42 @@
 ;;
 ;;; License: MIT
 
+;; Ensure Doom is always running out of this file's directory
 (setq user-emacs-directory (file-name-directory load-file-name)
       load-prefer-newer noninteractive)
 
+
+;;
+;; Optimize startup
+;;
+
+(unless noninteractive
+  (defvar doom--file-name-handler-alist
+    file-name-handler-alist)
+  (unless after-init-time
+    ;; A big contributor to long startup times is the garbage collector, so we
+    ;; up its memory threshold, temporarily and reset it later in
+    ;; `doom|finalize'.
+    (setq gc-cons-threshold 402653184
+          gc-cons-percentage 1.0
+          ;; consulted on every `require', `load' and various file reading
+          ;; functions. You get a minor speed up by nooping this.
+          file-name-handler-alist nil))
+
+  (defun doom|finalize ()
+    "Resets garbage collection settings to reasonable defaults (if you don't do
+this, you'll get stuttering and random freezes) and resets
+`file-name-handler-alist'."
+    (setq file-name-handler-alist doom--file-name-handler-alist
+          gc-cons-threshold 16777216
+          gc-cons-percentage 0.2))
+
+  (add-hook 'emacs-startup-hook #'doom|finalize)
+  (add-hook 'doom-reload-hook   #'doom|finalize))
+
+
+;;
+;; Bootstrap Doom
+;;
+
 (require 'core (concat user-emacs-directory "core/core"))