only require C++17 for swift-stdlib-tool

Author: salinas-miguel

tools/swift-stdlib-tool/CMakeLists.txt

@@ -2,7 +2,8 @@ add_swift_host_tool(swift-stdlib-tool
   swift-stdlib-tool.cpp
   SWIFT_COMPONENT compiler)
 
-set(CMAKE_CXX_STANDARD 17)
-set(CMAKE_CXX_STANDARD_REQUIRED True)
+set_target_properties(swift-stdlib-tool PROPERTIES
+  CXX_STANDARD 17
+  CXX_STANDARD_REQUIRED ON)
 
 target_link_libraries(swift-stdlib-tool PRIVATE)