gistfile1.el

(defun read-lines (file)
  "Return a list of lines in FILE."
  (with-temp-buffer
    (insert-file-contents file)
    (split-string
     (buffer-string) "\n" t)
    ) )

(defun jdv-split-path-from-file (lines)
  (let ((linelist (if (listp lines) lines (list lines)) ))
    (split-string (car linelist) ":" t)))

(let ((path-file (expand-file-name "~/.emacs_path")))
  (when (file-exists-p path-file)
    (setenv "PATH"
            (mapconcat 'identity 
                       (delete-dups 
                        (append
                         (jdv-split-path-from-file (read-lines path-file))
                         (split-string (getenv "PATH") ":" t))) ":"))))