fix(client-cpp): CMake 4 Thrift policy and Session.cpp cstring

Pass CMAKE_POLICY_VERSION_MINIMUM=3.5 when configuring Thrift 0.21 on CMake 4.x (VS2026 CI). Include <cstring> in Session.cpp for memcpy/strlen/strstr on strict Linux builds.

Author: hongzhi-gao

iotdb-client/client-cpp/cmake/FetchThrift.cmake

@@ -95,6 +95,8 @@ endif()
 # binary / library can immediately drive code generation and linking.
 # ---------------------------------------------------------------------------
 set(_thrift_cmake_args
+        # CMake 4.x rejects Thrift 0.21's cmake_minimum_required(3.0); set policy first.
+        "-DCMAKE_POLICY_VERSION_MINIMUM=3.5"
         "-DCMAKE_INSTALL_PREFIX=${_thrift_install}"
         "-DCMAKE_BUILD_TYPE=Release"
         "-DBUILD_JAVA=OFF"

iotdb-client/client-cpp/src/session/Session.cpp

@@ -19,6 +19,7 @@
 
 #include "Session.h"
 #include <algorithm>
+#include <cstring>
 #include <memory>
 #include <stack>
 #include <time.h>