Fix a couple more warnings

src/object.cpp

@@ -124,6 +124,7 @@ void zmq::object_t::process_command (command_t &cmd_)
         process_reaped ();
         break;
 
+    case command_t::done:
     default:
         zmq_assert (false);
     }

src/options.cpp

@@ -331,9 +331,12 @@ int zmq::options_t::setsockopt (int option_, const void *optval_,
                 return 0;
             }
         }
+    default:
+        {
+            errno = EINVAL;
+            return -1;
+        }
     }
-    errno = EINVAL;
-    return -1;
 }
 
 int zmq::options_t::getsockopt (int option_, void *optval_, size_t *optvallen_)

src/signaler.cpp

@@ -202,8 +202,8 @@ void zmq::signaler_t::recv ()
     //  one, return it back to the eventfd object.
     if (unlikely (dummy == 2)) {
         const uint64_t inc = 1;
-        ssize_t sz = write (w, &inc, sizeof (inc));
-        errno_assert (sz == sizeof (inc));
+        ssize_t sz2 = write (w, &inc, sizeof (inc));
+        errno_assert (sz2 == sizeof (inc));
         return;
     }