tools: Suppress request for warning options not existent in clang

tools: Suppress request for warning options not existent in clang

To allow building with clang, avoiding:

  error: unknown warning option '-Wstrict-aliasing=3'; did you mean '-Wstring-plus-int'? [-Werror,-Wunknown-warning-option]

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-xvthlvmhzfnt7jx73jgmaea1@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>