With two new methods, one to find the first match, returning its syscall
id and its index in whatever internal database it keeps the syscall
into, then one to find the next match, if any.

Implemented only on arches where we actually read the syscall table from
the kernel sources, i.e. x86-64 for now, all the others use the libaudit
method for which this returns -1, i.e. just stubs were added, with the
actual implementation using whatever libaudit functions for matching
that may be available.

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-i0sj4rxk1a63pfe9gl8z8irs@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>