perf llvm: Use strerror_r instead of the thread unsafe strerror one

Cc: Adrian Hunter <adrian.hunter@intel.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-5njrq9dltckgm624omw9ljgu@git.kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>