Now that the beautifiers are being split into multiple source and object
files, we will need more of them exported, do it for the 'fd' one, will
be used to augment the return of some syscalls that may return an 'fd',
such as fcntl(fd, F_DUPFD).

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-39sosu12hhywyunqf5s74ewf@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>