So that we don't always carry that __bpf_output__ map, leaving that to
the scripts wanting to use that facility.
'perf trace' will be changed to look if that map is present and only
setup the bpf-output events if so.
Cc: Adrian Hunter <email@example.com>
Cc: Jiri Olsa <firstname.lastname@example.org>
Cc: Namhyung Kim <email@example.com>
Cc: Wang Nan <firstname.lastname@example.org>
Link: https://email@example.comSigned-off-by: Arnaldo Carvalho de Melo <firstname.lastname@example.org>