💥 Drop Emacs 25.x support

Emacs 26.1 is Doom's new minimum supported version

Closes #2026

core/core-lib.el

@@ -3,41 +3,6 @@
 (require 'cl-lib)
 (require 'subr-x)
 
-;; DEPRECATED Polyfills
-(unless EMACS26+
-  (with-no-warnings
-    ;; `kill-current-buffer' was introduced in Emacs 26
-    (defalias 'kill-current-buffer #'kill-this-buffer)
-    ;; if-let and when-let were moved to (if|when)-let* in Emacs 26+ so we alias
-    ;; them for 25 users.
-    (defalias 'if-let* #'if-let)
-    (defalias 'when-let* #'when-let)
-
-    ;; `mapcan' was introduced in 26.1. `cl-mapcan' isn't a perfect replacement,
-    ;; but it's close enough.
-    (defalias 'mapcan #'cl-mapcan)
-
-    (defun alist-get (key alist &optional default remove testfn)
-      "Return the value associated with KEY in ALIST.
-If KEY is not found in ALIST, return DEFAULT.
-Use TESTFN to lookup in the alist if non-nil.  Otherwise, use `assq'.
-
-This is a generalized variable suitable for use with `setf'.
-When using it to set a value, optional argument REMOVE non-nil
-means to remove KEY from ALIST if the new value is `eql' to DEFAULT."
-      (ignore remove) ;;Silence byte-compiler.
-      (let ((x (if (not testfn)
-                   (assq key alist)
-                 ;; In Emacs<26, `assoc' has no testfn arg, so we have to
-                 ;; implement it ourselves
-                 (if testfn
-                     (cl-loop for entry in alist
-                              if (funcall testfn key entry)
-                              return entry)
-                   (assoc key alist)))))
-        (if x (cdr x) default)))))
-
-
 ;;
 ;;; Helpers