diff -Nur protobuf-3.6.1/cmake/CMakeLists.txt protobuf-3.6.1_patch/cmake/CMakeLists.txt
--- protobuf-3.6.1/cmake/CMakeLists.txt	2018-07-28 04:30:28.000000000 +0800
+++ protobuf-3.6.1_patch/cmake/CMakeLists.txt	2023-07-14 10:11:53.661304913 +0800
@@ -15,11 +15,11 @@
 # Project
 project(protobuf C CXX)
 
-# Add c++11 flags
+# Add c++14 flags
 if (CYGWIN)
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++11")
 else()
-  set(CMAKE_CXX_STANDARD 11)
+  set(CMAKE_CXX_STANDARD 14)
   set(CMAKE_CXX_STANDARD_REQUIRED ON)
   set(CMAKE_CXX_EXTENSIONS OFF)
 endif()