When building with
Ubuntu clang version 14.0.0-1ubuntu1.1

we run into the following compile error (seen on Linux ppc64le, probably also an error on x86_64) :

/jdk/src/hotspot/os/linux/cgroupV1Subsystem_linux.hpp:65:10: error: 'is_read_only' overrides a member function but is not marked 'override' [-Werror,-Winconsistent-missing-override]
    bool is_read_only() { return _read_only; }
         ^
/jdk/src/hotspot/os/linux/cgroupSubsystem_linux.hpp:108:18: note: overridden virtual function is here
    virtual bool is_read_only() = 0;
                 ^
In file included from /jdk/src/hotspot/os/linux/cgroupSubsystem_linux.cpp:30:
/jdk/src/hotspot/os/linux/cgroupV2Subsystem_linux.hpp:131:54: error: 'memory_controller' overrides a member function but is not marked 'override' [-Werror,-Winconsistent-missing-override]
    CachingCgroupController<CgroupMemoryController>* memory_controller() { return _memory; }
                                                     ^
/jdk/src/hotspot/os/linux/cgroupSubsystem_linux.hpp:235:62: note: overridden virtual function is here
    virtual CachingCgroupController<CgroupMemoryController>* memory_controller() = 0;