Oops, I was pretty lame today.  In a recipe, this is actually more
simply fixable with

--8<---------------cut here---------------start------------->8---
(add-before 'configure 'avoid-/bin/sh
  (lambda _
    (substitute* "configure" (("#!/bin/sh") ""))))
--8<---------------cut here---------------end--------------->8---

and one package seems to already be doing sth similar.  I am not sure
this warrants a bug report, then.  Sorry for the nuisance :)

Best,
Wojtek