() Jean-Christophe Helary <jean.christophe.helary@gmail.com>
() Tue, 20 Jun 2017 17:48:49 +0900

   (format "http%s://elpa.gnu.org/packages/"
            (if (gnutls-available-p) "s" ""))

I think this is fine, if a bit noisy.  You might also consider:

 (concat "a" nil "b")
 => "ab"

-- 
Thien-Thi Nguyen -----------------------------------------------
 (defun responsep (query)
   (pcase (context query)
     (`(technical ,ml) (correctp ml))
     ...))                              748E A0E8 1CB8 A748 9BFA
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