Unix.accept may raise an exception (typicall Unix.EINTR, even with sigpipe blocked ?)

This avoids the server to stop

src/Tiny_httpd.ml

@@ -1088,6 +1088,7 @@ let run (self:t) : (unit,_) result =
     while self.running do
       (* limit concurrency *)
       Sem_.acquire 1 self.sem_max_connections;
+      try
         let client_sock, _ = Unix.accept sock in
         self.new_thread
           (fun () ->
@@ -1099,6 +1100,9 @@ let run (self:t) : (unit,_) result =
               Sem_.release 1 self.sem_max_connections;
               raise e
           );
+      with e ->
+        Printf.eprintf "accept raised an exception: %s"
+           (Printexc.to_string e)
     done;
     Ok ()
   with e -> Error e