[meta-oe] abseil-cpp: Set CMAKE_CXX_STANDARD to 17

The compiler defaults to C++ < 17 which causes build failures.
Abseil requires C++17 or higher, so explicitly set CMAKE_CXX_STANDARD=17
to ensure the build uses the correct C++ standard.

Error:
CMake Error at CMake/AbseilDll.cmake:745 (message):
  The compiler defaults to or is configured for C++ < 17.  C++ >= 17 is
  required and Abseil and all libraries that use Abseil must use the same C++
  language standard

Signed-off-by: Yogesh Tyagi <yogesh.tyagi@intel.com>
---
 meta-oe/recipes-devtools/abseil-cpp/abseil-cpp_20260107.0.bb | 1 +
 1 file changed, 1 insertion(+)

> -----Original Message-----
> From: openembedded-devel@lists.openembedded.org <openembedded-devel@lists.openembedded.org> On Behalf Of Yogesh Tyagi via lists.openembedded.org
> Sent: den 2 februari 2026 20:17
> To: openembedded-devel@lists.openembedded.org
> Cc: yogesh.tyagi@intel.com
> Subject: [oe] [meta-oe][PATCH] abseil-cpp: Set CMAKE_CXX_STANDARD to 17
> 
> The compiler defaults to C++ < 17 which causes build failures.
> Abseil requires C++17 or higher, so explicitly set CMAKE_CXX_STANDARD=17
> to ensure the build uses the correct C++ standard.
> 
> Error:
> CMake Error at CMake/AbseilDll.cmake:745 (message):
>   The compiler defaults to or is configured for C++ < 17.  C++ >= 17 is
>   required and Abseil and all libraries that use Abseil must use the same C++
>   language standard
> 
> Signed-off-by: Yogesh Tyagi <yogesh.tyagi@intel.com>
> ---
>  meta-oe/recipes-devtools/abseil-cpp/abseil-cpp_20260107.0.bb | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/meta-oe/recipes-devtools/abseil-cpp/abseil-cpp_20260107.0.bb b/meta-oe/recipes-devtools/abseil-cpp/abseil-cpp_20260107.0.bb
> index e2bce0be11..d4475ee73a 100644
> --- a/meta-oe/recipes-devtools/abseil-cpp/abseil-cpp_20260107.0.bb
> +++ b/meta-oe/recipes-devtools/abseil-cpp/abseil-cpp_20260107.0.bb
> @@ -21,6 +21,7 @@ inherit cmake
>  EXTRA_OECMAKE = "-DBUILD_SHARED_LIBS=ON \
>                   -DBUILD_TESTING=OFF    \
>                   -DABSL_ENABLE_INSTALL=ON \
> +                 -DCMAKE_CXX_STANDARD=17 \
>                  "
>  #  riscv32-yoe-linux-ld.lld: error: undefined reference: __atomic_store_8
>  #  >>> referenced by <recipe-sysroot>/usr/lib/libabsl_flags_internal.so.2505.0.0 (disallowed by --no-allow-shlib-undefined)
> --
> 2.34.1

I am not sure this is the correct thing to do. This means that for target, 
you will now downgrade the C++ standard when building abseil. However, as 
it says, all libraries that use abseil must use the same C++ standard. This 
will thus no longer be the case, unless all users of abseil are also 
modified to use C++17.

I believe the error you are seeing comes from building abseil-native, i.e., 
the native compiler you use uses an older C++ standard by default. But also 
in this case, just changing it for abseil is probably not the right thing to 
do.

The correct solution, I believe, is to use a newer native compiler. This may 
mean that you will have to use a buildtools tarball unless you can upgrade 
your host system.

//Peter