When project is top-level, force C++17

CMakeLists.txt

@@ -50,6 +50,9 @@ list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}/cmake")
 include(enable_extensions)
 
 if (PROJECT_IS_TOP_LEVEL)
+    set(CMAKE_CXX_STANDARD 17)
+    set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
     set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
     set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
     set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)

src/configuration/CMakeLists.txt

@@ -55,4 +55,5 @@ target_compile_definitions(configuration
         DRAMSYS_RESOURCE_DIR="${DRAMSYS_RESOURCE_DIR}"
 )
 
+target_compile_features(configuration PUBLIC cxx_std_17)
 add_library(DRAMSys::config ALIAS configuration)