Avoid gratuitous errors in 'url-retrieve-synchronously'

* lisp/url/url-http.el (url-http-debug):
* lisp/url/url-util.el (url-debug): Don't signal an error if
quit-flag is non-nil, but not t.  This could happen because
some unrelated code is running inside while-no-input.
(Bug#34763)

lisp/url/url-http.el

@@ -150,7 +150,7 @@ request.")
 ;; These routines will allow us to implement persistent HTTP
 ;; connections.
 (defsubst url-http-debug (&rest args)
-  (if quit-flag
+  (if (eq quit-flag t)
       (let ((proc (get-buffer-process (current-buffer))))
 	;; The user hit C-g, honor it!  Some things can get in an
 	;; incredibly tight loop (chunked encoding)

lisp/url/url-util.el

@@ -61,7 +61,7 @@ If a list, it is a list of the types of messages to be logged."
 
 ;;;###autoload
 (defun url-debug (tag &rest args)
-  (if quit-flag
+  (if (eq quit-flag t)
       (error "Interrupted!"))
   (if (or (eq url-debug t)
 	  (numberp url-debug)