Add C++ standard requirements to CMake module configurations

- Enforce `CMAKE_CXX_STANDARD` and `CMAKE_CXX_STANDARD_REQUIRED` across all relevant submodules (`onetbb`, `libenvpp`, `json`, `gtest`).

Author: allnes

cmake/gtest.cmake

@@ -7,6 +7,8 @@ ExternalProject_Add(ppc_googletest
         INSTALL_DIR       "${CMAKE_CURRENT_BINARY_DIR}/ppc_googletest/install"
         CONFIGURE_COMMAND "${CMAKE_COMMAND}" -S "${CMAKE_SOURCE_DIR}/3rdparty/googletest/" -B "${CMAKE_CURRENT_BINARY_DIR}/ppc_googletest/build/"
         -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER} -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER} -G${CMAKE_GENERATOR} -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}
-        -D CMAKE_C_COMPILER_LAUNCHER=${CMAKE_C_COMPILER_LAUNCHER} -D CMAKE_CXX_COMPILER_LAUNCHER=${CMAKE_CXX_COMPILER_LAUNCHER} -Dgtest_force_shared_crt=ON -DCMAKE_CXX_FLAGS="-w" -DCMAKE_C_FLAGS="-w"
+        -D CMAKE_C_COMPILER_LAUNCHER=${CMAKE_C_COMPILER_LAUNCHER} -D CMAKE_CXX_COMPILER_LAUNCHER=${CMAKE_CXX_COMPILER_LAUNCHER}
+        -Dgtest_force_shared_crt=ON -DCMAKE_CXX_FLAGS="-w" -DCMAKE_C_FLAGS="-w"
+        -D CMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD} -D CMAKE_CXX_STANDARD_REQUIRED=ON
         BUILD_COMMAND     "${CMAKE_COMMAND}" --build "${CMAKE_CURRENT_BINARY_DIR}/ppc_googletest/build" --config ${CMAKE_BUILD_TYPE} --parallel
         INSTALL_COMMAND   "${CMAKE_COMMAND}" --install "${CMAKE_CURRENT_BINARY_DIR}/ppc_googletest/build" --prefix "${CMAKE_CURRENT_BINARY_DIR}/ppc_googletest/install")

cmake/json.cmake

@@ -8,5 +8,6 @@ ExternalProject_Add(ppc_json
         CONFIGURE_COMMAND "${CMAKE_COMMAND}" -S "${CMAKE_SOURCE_DIR}/3rdparty/json/" -B "${CMAKE_CURRENT_BINARY_DIR}/ppc_json/build/"
         -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER} -G${CMAKE_GENERATOR} -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}
         -D CMAKE_C_COMPILER_LAUNCHER=${CMAKE_C_COMPILER_LAUNCHER} -D CMAKE_CXX_COMPILER_LAUNCHER=${CMAKE_CXX_COMPILER_LAUNCHER}
+        -D CMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD} -D CMAKE_CXX_STANDARD_REQUIRED=ON
         BUILD_COMMAND     "${CMAKE_COMMAND}" --build "${CMAKE_CURRENT_BINARY_DIR}/ppc_json/build" --config ${CMAKE_BUILD_TYPE} --parallel
         INSTALL_COMMAND   "${CMAKE_COMMAND}" --install "${CMAKE_CURRENT_BINARY_DIR}/ppc_json/build" --prefix "${CMAKE_CURRENT_BINARY_DIR}/ppc_json/install")

cmake/libenvpp.cmake

@@ -10,6 +10,7 @@ ExternalProject_Add(ppc_libenvpp
         CONFIGURE_COMMAND "${CMAKE_COMMAND}" -S "${CMAKE_SOURCE_DIR}/3rdparty/libenvpp/" -B "${CMAKE_CURRENT_BINARY_DIR}/ppc_libenvpp/build/"
         -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER} -G${CMAKE_GENERATOR} -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}
         -D CMAKE_C_COMPILER_LAUNCHER=${CMAKE_C_COMPILER_LAUNCHER} -D CMAKE_CXX_COMPILER_LAUNCHER=${CMAKE_CXX_COMPILER_LAUNCHER}
+        -D CMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD} -D CMAKE_CXX_STANDARD_REQUIRED=ON
         BUILD_COMMAND     "${CMAKE_COMMAND}" --build "${CMAKE_CURRENT_BINARY_DIR}/ppc_libenvpp/build" --config ${CMAKE_BUILD_TYPE} --parallel
         INSTALL_COMMAND   "${CMAKE_COMMAND}" --install "${CMAKE_CURRENT_BINARY_DIR}/ppc_libenvpp/build" --prefix "${CMAKE_CURRENT_BINARY_DIR}/ppc_libenvpp/install")
 

cmake/onetbb.cmake

@@ -19,6 +19,7 @@ ExternalProject_Add(ppc_onetbb
                       -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER} -DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}
                       -DCMAKE_C_COMPILER_LAUNCHER=${CMAKE_C_COMPILER_LAUNCHER} -DCMAKE_CXX_COMPILER_LAUNCHER=${CMAKE_CXX_COMPILER_LAUNCHER}
                       -G${CMAKE_GENERATOR} -DTBB_TEST=OFF -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}
+                      -D CMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD} -D CMAKE_CXX_STANDARD_REQUIRED=ON
     BUILD_COMMAND     "${CMAKE_COMMAND}" --build "${CMAKE_CURRENT_BINARY_DIR}/ppc_onetbb/build" --config ${CMAKE_BUILD_TYPE} --parallel
     INSTALL_COMMAND   "${CMAKE_COMMAND}" --install "${CMAKE_CURRENT_BINARY_DIR}/ppc_onetbb/build" --prefix "${CMAKE_CURRENT_BINARY_DIR}/ppc_onetbb/install"
     TEST_COMMAND      ${ppc_onetbb_TEST_COMMAND}

modules/core/performance/tests/perf_tests.cpp

@@ -242,14 +242,10 @@ struct Type {};
 class Another {};
 }  // namespace my
 
-namespace {
-struct NoNamespace {};
-}  // anonymous namespace
-
 template <typename T>
 class GetNamespaceTest : public ::testing::Test {};
 
-using TestTypes = ::testing::Types<my::nested::Type, my::Another, NoNamespace, int, std::vector<int>>;
+using TestTypes = ::testing::Types<my::nested::Type, my::Another, int, std::vector<int>>;
 
 TYPED_TEST_SUITE(GetNamespaceTest, TestTypes);
 
@@ -260,8 +256,6 @@ TYPED_TEST(GetNamespaceTest, ExtractsNamespaceCorrectly) {
     EXPECT_EQ(ns, "my::nested");
   } else if constexpr (std::is_same_v<TypeParam, my::Another>) {
     EXPECT_EQ(ns, "my");
-  } else if constexpr (std::is_same_v<TypeParam, NoNamespace>) {
-    EXPECT_EQ(ns, "");
   } else if constexpr (std::is_same_v<TypeParam, int>) {
     EXPECT_EQ(ns, "");
   } else if constexpr (std::is_same_v<TypeParam, std::vector<int>>) {