[Doc] Added C++17 cmake option (#38432)

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Closes #38432

COPYBARA_INTEGRATE_REVIEW=https://github.com/grpc/grpc/pull/38432 from veblush:cpp17-doc 4c7dce0783
PiperOrigin-RevId: 714143397

BUILDING.md

@@ -126,7 +126,7 @@ Run from the grpc directory after cloning the repo with --recursive or updating
 ```
 $ mkdir -p cmake/build
 $ cd cmake/build
-$ cmake ../..
+$ cmake -DCMAKE_CXX_STANDARD=17 ../..
 $ make
 ```
 
@@ -143,7 +143,7 @@ you will be able to browse and build the code.
 > @rem Run from grpc directory after cloning the repo with --recursive or updating submodules.
 > md .build
 > cd .build
-> cmake .. -G "Visual Studio 17 2022"
+> cmake -G "Visual Studio 17 2022" -DCMAKE_CXX_STANDARD=17 ..
 > cmake --build . --config Release
 ```
 
@@ -159,7 +159,7 @@ installed to be able to compile the C/C++ sources.
 > md build
 > cd build
 > call "%VS140COMNTOOLS%..\..\VC\vcvarsall.bat" x64
-> cmake ..\.. -GNinja -DCMAKE_BUILD_TYPE=Release
+> cmake -GNinja -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_STANDARD=17 ..\..
 > cmake --build .
 ```
 
@@ -174,6 +174,15 @@ at your own risk.
 - you've been warned that there are some important drawbacks and some things might not work at all or will be broken in interesting ways.
 - we don't have extensive testing for DLL builds in place (to avoid maintenance costs, increased test duration etc.) so regressions / build breakages might occur
 
+### Consistent standard C++ version
+
+To avoid build errors when building gRPC and its dependencies (especially from gRPC C++ 1.70 onwards),
+ensure all CMake builds use the same C++ standard (at least C++17).
+This is crucial because gRPC C++ 1.70 requires at least C++17, and Abseil, a gRPC dependency,
+provides different APIs based on the C++ version.
+For instance, `absl::string_view` is implemented differently before and after C++17.
+Using a consistent C++ version prevents inconsistencies and ensures compatibility across the project.
+
 ### Dependency management
 
 gRPC's CMake build system has two options for handling dependencies.
@@ -217,6 +226,7 @@ how to install dependencies with cmake before proceeding to installing gRPC itse
 # NOTE: all of gRPC's dependencies need to be already installed
 $ cmake ../.. -DgRPC_INSTALL=ON                \
               -DCMAKE_BUILD_TYPE=Release       \
+              -DCMAKE_CXX_STANDARD=17          \
               -DgRPC_ABSL_PROVIDER=package     \
               -DgRPC_CARES_PROVIDER=package    \
               -DgRPC_PROTOBUF_PROVIDER=package \

doc/command_line_tool.md

@@ -53,7 +53,7 @@ Once the prerequisites are satisfied, you can build with cmake:
 ```
 $ mkdir -p cmake/build
 $ cd cmake/build
-$ cmake -DgRPC_BUILD_TESTS=ON ../..
+$ cmake -DgRPC_BUILD_TESTS=ON -DCMAKE_CXX_STANDARD=17 ../..
 $ make grpc_cli
 ```
 

src/cpp/README.md

@@ -30,10 +30,10 @@ Therefore, gRPC supports several major build systems, which should satisfy most
 
 | Operating System | Architectures | Versions | Support Level |
 |------------------|---------------|----------|---------------|
-| Linux - Debian, Ubuntu, CentOS | x86, x64      | clang 7+, GCC 7.3+     | Officially Supported |
+| Linux - Debian, Ubuntu, CentOS | x86, x64      | clang 7+, GCC 7.5+     | Officially Supported |
 | Windows 10+                    | x86, x64      | Visual Studio 2022+    | Officially Supported |
 | MacOS                          | x64, ARM64    | XCode 12+              | Officially Supported |
-| Linux - Others                 | x86, x64      | clang 7+, GCC 7.3+     | Best Effort          |
+| Linux - Others                 | x86, x64      | clang 7+, GCC 7.5+     | Best Effort          |
 | Linux                          | ARM64         |                        | Best Effort          |
 | iOS                            |               |                        | Best Effort          |
 | Android                        |               |                        | Best Effort          |
@@ -77,6 +77,17 @@ can be used for targeting the Android platform.
 
 To build gRPC C++ from source, follow the [BUILDING guide](../../BUILDING.md).
 
+To ensure all libraries in your CMake project compile with the same C++ version
+(e.g., C++17), explicitly specify the standard:
+
+```cmake
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+```
+
+This configuration enforces the use of C++17 for all targets and avoids potential
+inconsistencies or errors due to different C++ versions being used.
+
 ### find_package
 
 The canonical way to discover dependencies in CMake is the