perf tools: Add flex support for parse_events_error

perf tools: Add flex support for parse_events_error

Allowing flex parser to report back event parsing error, like:

  $ perf record -e cycles,cache-mises ls
  event syntax error: '..es,cache-mises'
                                 \___ parser error
  ...

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1429729824-13932-3-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>