fix:taos.dll export taosDatatype

include/client/taos.h

@@ -149,7 +149,7 @@ DLL_EXPORT TAOS      *taos_connect(const char *ip, const char *user, const char
 DLL_EXPORT TAOS *taos_connect_auth(const char *ip, const char *user, const char *auth, const char *db, uint16_t port);
 DLL_EXPORT void  taos_close(TAOS *taos);
 
-const char *taos_data_type(int type);
+DLL_EXPORT const char *taos_data_type(int type);
 
 DLL_EXPORT TAOS_STMT *taos_stmt_init(TAOS *taos);
 DLL_EXPORT TAOS_STMT *taos_stmt_init_with_reqid(TAOS *taos, int64_t reqid);