autoloads load file is wrong in Emacs 28 when using symlink

[Jiacai Liu]

Hi,

I build emacs-28 branch with commit 3f998a3fc8 on macOS, it seems 
autoloads load-file is different from emacs 27 when 
package-install. Take undo-tree as an example:

;; 27
(autoload 'undo-tree-mode "undo-tree" "some docstring" t nil)

;; 28
(autoload 'undo-tree-mode 
"../../../../../../.config/emacs/elpa/undo-tree-0.7.5/undo-tree" 
"some docstring" t nil)


After some debugging, I found this issue is related with symlink.

I usually put all my dotfiles in a git repo(emacs included), and 
soft link to ~/.config/emacs, then load file is wrong as above.
If I put config directly at ~/.config/emacs, load file is the same 
as Emacs 27.