Problem: mingw build broken

Solution: check correct preprocessor define in test_reconnect_ivl to match the
test invocation

tests/test_reconnect_ivl.cpp

@@ -101,7 +101,7 @@ int main (void)
     setup_test_environment ();
 
     UNITY_BEGIN ();
-#if !defined(ZMQ_HAVE_WINDOWS) && !defined(ZMQ_HAVE_GNU)
+#if defined(ZMQ_HAVE_IPC) && !defined(ZMQ_HAVE_GNU)
     RUN_TEST (test_reconnect_ivl_ipc);
 #endif
     RUN_TEST (test_reconnect_ivl_tcp_ipv4);