fix windows compile error

source/libs/tdb/test/tdbTest.cpp

@@ -515,7 +515,7 @@ TEST(tdb_test, multi_thread_query) {
 
   // start a transaction
   txnid++;
-  txn = {.flags = TDB_TXN_WRITE | TDB_TXN_READ_UNCOMMITTED,
+  txn = (TXN){.flags = TDB_TXN_WRITE | TDB_TXN_READ_UNCOMMITTED,
               .txnId = -1,
               .xMalloc = poolMalloc,
               .xFree = poolFree,
@@ -554,7 +554,7 @@ TEST(tdb_test, multi_thread_query) {
     TXN   txn;
 
     SPoolMem *pPool = openPool();
-    txn = {.flags = 0, .txnId = 0, .xMalloc = poolMalloc, .xFree = poolFree, .xArg = pPool};
+    txn = (TXN){.flags = 0, .txnId = 0, .xMalloc = poolMalloc, .xFree = poolFree, .xArg = pPool};
 
     ret = tdbTbcOpen(pDb, &pDBC, &txn);
     GTEST_ASSERT_EQ(ret, 0);