Set the HOME environment variable in Emacs package debug script instead of using it on command line.

[Hongyi Zhao]

I've writtent the following Emacs package debug script which can be
run by `$ bash /home/werner/.emacs.d/debug/.emacs.d/init.el`:

```emacs-lisp
#!/usr/bin/env bash
:;# $ realpath init.el
:;# /home/werner/.emacs.d/debug/.emacs.d/init.el
:; HOME=$(dirname $(dirname $(realpath -e $0))) proxychains-ng-socks5
/usr/local/bin/emacs -- "$@"; exit

;;Bootstrap straight
(defvar bootstrap-version)
(let ((bootstrap-file
       (expand-file-name "straight/repos/straight.el/bootstrap.el"
user-emacs-directory))
      (bootstrap-version 5))
  (unless (file-exists-p bootstrap-file)
    (with-current-buffer
        (url-retrieve-synchronously
         
"https://raw.githubusercontent.com/raxod502/straight.el/develop/install.el";
         'silent 'inhibit-cookies)
      (goto-char (point-max))
      (eval-print-last-sexp)))
  (load bootstrap-file nil 'nomessage))
(straight-use-package 'use-package)
(setq straight-use-package-by-default t)

(use-package company
  :demand t
  :hook
  (after-init . global-company-mode))
```
I want to set the HOME environment variable in the lisp code, so it
will not disturb the system environment variable settings.

Any tips for achieving this goal?

Regards,
HZ