So that we can build on older systems where otherwise we would end up
with:

    CC       /tmp/build/perf/trace/beauty/ioctl.o
  trace/beauty/ioctl.c: In function 'ioctl__scnprintf_tty_cmd':
  trace/beauty/ioctl.c:25:17: error: 'TIOCGEXCL' undeclared (first use in this function)
  trace/beauty/ioctl.c:25:17: note: each undeclared identifier is reported only once for each function it appears in
  trace/beauty/ioctl.c:25:2: error: array index in initializer not of integer type
  trace/beauty/ioctl.c:25:2: error: (near initialization for 'ioctl_tty_cmd')

This way we can build a tool on an older system and it will still be
capable of processing perf.data files generated on newer systems.

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-8qvkv6txwuzua6d0yvt65wl3@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>