Effectively, this change

* bumps the minimum CMake version to 3.22
* bumps the minimum C++ version to C++17

This aligns with the Google C++ support policy at
https://github.com/google/oss-policies-info/blob/main/foundational-cxx-support-matrix.md

PiperOrigin-RevId: 881717521

Author: pwnall

CMakeLists.txt

@@ -2,7 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file. See the AUTHORS file for names of contributors.
 
-cmake_minimum_required(VERSION 3.9)
+cmake_minimum_required(VERSION 3.22)
 # Keep the version below in sync with the one in db.h
 project(leveldb VERSION 1.23.0 LANGUAGES C CXX)
 
@@ -16,8 +16,8 @@ endif(NOT CMAKE_C_STANDARD)
 
 # C++ standard can be overridden when this is used as a sub-project.
 if(NOT CMAKE_CXX_STANDARD)
-  # This project requires C++11.
-  set(CMAKE_CXX_STANDARD 11)
+  # This project requires C++17.
+  set(CMAKE_CXX_STANDARD 17)
   set(CMAKE_CXX_STANDARD_REQUIRED ON)
   set(CMAKE_CXX_EXTENSIONS OFF)
 endif(NOT CMAKE_CXX_STANDARD)