Build errors on OSX

bash-5.2$ cmake --workflow appleclang-release --fresh 
Executing workflow step 1 of 3: configure preset "appleclang-release"

-- The CXX compiler identification is AppleClang 16.0.0.16000026
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/g++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- CMAKE_CXX_SCAN_FOR_MODULES="0" ; CMAKE_CXX_MODULE_STD="" ; CMAKE_CXX_COMPILER_IMPORT_STD=""
-- Compiler is: AppleClang version: 16.0.0.16000026
-- CMake is: 4.0.20250529-gdf894a1 modules scan: 0
Cloning into 'catch2-src'...
HEAD is now at 2b60af89 v3.8.1
-- Performing Test HAVE_FLAG__ffile_prefix_map__Users_clausklein_Workspace_cpp_cxx23_scope_build_appleclang_release__deps_catch2_src__
-- Performing Test HAVE_FLAG__ffile_prefix_map__Users_clausklein_Workspace_cpp_cxx23_scope_build_appleclang_release__deps_catch2_src__ - Success
Examples to be built: scope_example;unique_resource;unique_resource-file
-- Configuring done (8.9s)
-- Generating done (0.2s)
-- Build files have been written to: /Users/clausklein/Workspace/cpp/cxx23/scope/build/appleclang-release

Executing workflow step 2 of 3: build preset "appleclang-release"

[108/122] Building CXX object examples/CMakeFiles/scope_example.dir/scope_example.cpp.o
FAILED: examples/CMakeFiles/scope_example.dir/scope_example.cpp.o 
ccache /usr/bin/g++  -I/Users/clausklein/Workspace/cpp/cxx23/scope/include -O3  -O2 -g -DNDEBUG -std=gnu++20 -MD -MT examples/CMakeFiles/scope_example.dir/scope_example.cpp.o -MF examples/CMakeFiles/scope_example.dir/scope_example.cpp.o.d -o examples/CMakeFiles/scope_example.dir/scope_example.cpp.o -c /Users/clausklein/Workspace/cpp/cxx23/scope/examples/scope_example.cpp
In file included from /Users/clausklein/Workspace/cpp/cxx23/scope/examples/scope_example.cpp:3:
/Users/clausklein/Workspace/cpp/cxx23/scope/include/beman/scope/scope.hpp:18:10: fatal error: 'experimental/scope' file not found
   18 | #include <experimental/scope> //todo unconditional for unique_resource
      |          ^~~~~~~~~~~~~~~~~~~~
1 error generated.
[110/122] Building CXX object tests/CMakeFiles/test.scope_success.dir/scope_success.test.cpp.o
FAILED: tests/CMakeFiles/test.scope_success.dir/scope_success.test.cpp.o 
ccache /usr/bin/g++  -I/Users/clausklein/Workspace/cpp/cxx23/scope/include -isystem /Users/clausklein/Workspace/cpp/cxx23/scope/build/appleclang-release/_deps/catch2-src/src/catch2/.. -isystem /Users/clausklein/Workspace/cpp/cxx23/scope/build/appleclang-release/_deps/catch2-build/generated-includes -O3  -O2 -g -DNDEBUG -std=gnu++20 -MD -MT tests/CMakeFiles/test.scope_success.dir/scope_success.test.cpp.o -MF tests/CMakeFiles/test.scope_success.dir/scope_success.test.cpp.o.d -o tests/CMakeFiles/test.scope_success.dir/scope_success.test.cpp.o -c /Users/clausklein/Workspace/cpp/cxx23/scope/tests/scope_success.test.cpp
In file included from /Users/clausklein/Workspace/cpp/cxx23/scope/tests/scope_success.test.cpp:3:
/Users/clausklein/Workspace/cpp/cxx23/scope/include/beman/scope/scope.hpp:18:10: fatal error: 'experimental/scope' file not found
   18 | #include <experimental/scope> //todo unconditional for unique_resource
      |          ^~~~~~~~~~~~~~~~~~~~
1 error generated.
[111/122] Building CXX object tests/CMakeFiles/test.scope_exit.dir/scope_exit.test.cpp.o
FAILED: tests/CMakeFiles/test.scope_exit.dir/scope_exit.test.cpp.o 
ccache /usr/bin/g++  -I/Users/clausklein/Workspace/cpp/cxx23/scope/include -isystem /Users/clausklein/Workspace/cpp/cxx23/scope/build/appleclang-release/_deps/catch2-src/src/catch2/.. -isystem /Users/clausklein/Workspace/cpp/cxx23/scope/build/appleclang-release/_deps/catch2-build/generated-includes -O3  -O2 -g -DNDEBUG -std=gnu++20 -MD -MT tests/CMakeFiles/test.scope_exit.dir/scope_exit.test.cpp.o -MF tests/CMakeFiles/test.scope_exit.dir/scope_exit.test.cpp.o.d -o tests/CMakeFiles/test.scope_exit.dir/scope_exit.test.cpp.o -c /Users/clausklein/Workspace/cpp/cxx23/scope/tests/scope_exit.test.cpp
In file included from /Users/clausklein/Workspace/cpp/cxx23/scope/tests/scope_exit.test.cpp:5:
/Users/clausklein/Workspace/cpp/cxx23/scope/include/beman/scope/scope.hpp:18:10: fatal error: 'experimental/scope' file not found
   18 | #include <experimental/scope> //todo unconditional for unique_resource
      |          ^~~~~~~~~~~~~~~~~~~~
1 error generated.
[112/122] Building CXX object tests/CMakeFiles/test.scope_fail.dir/scope_fail.test.cpp.o
FAILED: tests/CMakeFiles/test.scope_fail.dir/scope_fail.test.cpp.o 
ccache /usr/bin/g++  -I/Users/clausklein/Workspace/cpp/cxx23/scope/include -isystem /Users/clausklein/Workspace/cpp/cxx23/scope/build/appleclang-release/_deps/catch2-src/src/catch2/.. -isystem /Users/clausklein/Workspace/cpp/cxx23/scope/build/appleclang-release/_deps/catch2-build/generated-includes -O3  -O2 -g -DNDEBUG -std=gnu++20 -MD -MT tests/CMakeFiles/test.scope_fail.dir/scope_fail.test.cpp.o -MF tests/CMakeFiles/test.scope_fail.dir/scope_fail.test.cpp.o.d -o tests/CMakeFiles/test.scope_fail.dir/scope_fail.test.cpp.o -c /Users/clausklein/Workspace/cpp/cxx23/scope/tests/scope_fail.test.cpp
In file included from /Users/clausklein/Workspace/cpp/cxx23/scope/tests/scope_fail.test.cpp:3:
/Users/clausklein/Workspace/cpp/cxx23/scope/include/beman/scope/scope.hpp:18:10: fatal error: 'experimental/scope' file not found
   18 | #include <experimental/scope> //todo unconditional for unique_resource
      |          ^~~~~~~~~~~~~~~~~~~~
1 error generated.
[113/122] Building CXX object tests/CMakeFiles/test.unique_resource.dir/unique_resource.test.cpp.o
FAILED: tests/CMakeFiles/test.unique_resource.dir/unique_resource.test.cpp.o 
ccache /usr/bin/g++  -I/Users/clausklein/Workspace/cpp/cxx23/scope/include -isystem /Users/clausklein/Workspace/cpp/cxx23/scope/build/appleclang-release/_deps/catch2-src/src/catch2/.. -isystem /Users/clausklein/Workspace/cpp/cxx23/scope/build/appleclang-release/_deps/catch2-build/generated-includes -O3  -O2 -g -DNDEBUG -std=gnu++20 -MD -MT tests/CMakeFiles/test.unique_resource.dir/unique_resource.test.cpp.o -MF tests/CMakeFiles/test.unique_resource.dir/unique_resource.test.cpp.o.d -o tests/CMakeFiles/test.unique_resource.dir/unique_resource.test.cpp.o -c /Users/clausklein/Workspace/cpp/cxx23/scope/tests/unique_resource.test.cpp
In file included from /Users/clausklein/Workspace/cpp/cxx23/scope/tests/unique_resource.test.cpp:3:
/Users/clausklein/Workspace/cpp/cxx23/scope/include/beman/scope/scope.hpp:18:10: fatal error: 'experimental/scope' file not found
   18 | #include <experimental/scope> //todo unconditional for unique_resource
      |          ^~~~~~~~~~~~~~~~~~~~
1 error generated.
[114/122] Building CXX object examples/CMakeFiles/unique_resource.dir/unique_resource.cpp.o
FAILED: examples/CMakeFiles/unique_resource.dir/unique_resource.cpp.o 
ccache /usr/bin/g++  -I/Users/clausklein/Workspace/cpp/cxx23/scope/include -O3  -O2 -g -DNDEBUG -std=gnu++20 -MD -MT examples/CMakeFiles/unique_resource.dir/unique_resource.cpp.o -MF examples/CMakeFiles/unique_resource.dir/unique_resource.cpp.o.d -o examples/CMakeFiles/unique_resource.dir/unique_resource.cpp.o -c /Users/clausklein/Workspace/cpp/cxx23/scope/examples/unique_resource.cpp
In file included from /Users/clausklein/Workspace/cpp/cxx23/scope/examples/unique_resource.cpp:5:
/Users/clausklein/Workspace/cpp/cxx23/scope/include/beman/scope/scope.hpp:18:10: fatal error: 'experimental/scope' file not found
   18 | #include <experimental/scope> //todo unconditional for unique_resource
      |          ^~~~~~~~~~~~~~~~~~~~
1 error generated.
[115/122] Building CXX object examples/CMakeFiles/unique_resource-file.dir/unique_resource-file.cpp.o
FAILED: examples/CMakeFiles/unique_resource-file.dir/unique_resource-file.cpp.o 
ccache /usr/bin/g++  -I/Users/clausklein/Workspace/cpp/cxx23/scope/include -O3  -O2 -g -DNDEBUG -std=gnu++20 -MD -MT examples/CMakeFiles/unique_resource-file.dir/unique_resource-file.cpp.o -MF examples/CMakeFiles/unique_resource-file.dir/unique_resource-file.cpp.o.d -o examples/CMakeFiles/unique_resource-file.dir/unique_resource-file.cpp.o -c /Users/clausklein/Workspace/cpp/cxx23/scope/examples/unique_resource-file.cpp
In file included from /Users/clausklein/Workspace/cpp/cxx23/scope/examples/unique_resource-file.cpp:6:
/Users/clausklein/Workspace/cpp/cxx23/scope/include/beman/scope/scope.hpp:18:10: fatal error: 'experimental/scope' file not found
   18 | #include <experimental/scope> //todo unconditional for unique_resource
      |          ^~~~~~~~~~~~~~~~~~~~
1 error generated.
ninja: build stopped: subcommand failed.
bash-5.2$

diff --git a/cmake/appleclang-toolchain.cmake b/cmake/appleclang-toolchain.cmake
index bc12103..2ca3652 100644
--- a/cmake/appleclang-toolchain.cmake
+++ b/cmake/appleclang-toolchain.cmake
@@ -16,8 +16,8 @@
 
 include_guard(GLOBAL)
 
-set(CMAKE_C_COMPILER clang)
-set(CMAKE_CXX_COMPILER clang++)
+set(CMAKE_C_COMPILER gcc)
+set(CMAKE_CXX_COMPILER g++)
 
 if(BEMAN_BUILDSYS_SANITIZER STREQUAL "MaxSan")
     set(SANITIZER_FLAGS