Here is the solution I came up with, following the hints given by [[https://github.com/progfolio/elpaca/issues/191]]

 (defun ded:elpaca-build-dir (p)
    "Return the elpaca build directory for package symbol p"
    (-first-item
     (f-directories elpaca-builds-directory
  	                (lambda (dir) (string-match-p (concat "^" (symbol-name p) "$") (f-filename dir))))))

  (use-package auctex
    :elpaca (auctex :pre-build (("./autogen.sh")
                                ("./configure" "--without-texmf-dir" "--with-lispdir=.")
                                ("make")
                                ("install-info" "doc/auctex.info" "doc/dir")
                                ("install-info" "doc/preview-latex.info" "doc/dir")))
    :mode (("\\.tex\\'" . TeX-latex-mode)
           ("\\.tex\\.erb\\'" . TeX-latex-mode)
           ("\\.etx\\'" . TeX-latex-mode))
    :init
    (add-to-list 'Info-additional-directory-list (f-join (ded:elpaca-build-dir 'auctex) "doc"))
    (add-hook 'tex-mode-hook
              (lambda ()
                (load "auctex.el")
                (setq TeX-command-extra-options "-shell-escape")))
    :config
    (setq-default TeX-global-PDF-mode 1)
    (setq-default  preview-scale-function 1.5)
    (setq TeX-auto-save t
          TeX-parse-self t
          default-truncate-lines t
          TeX-save-query nil
          TeX-source-correlate-method 'synctex))