perf strlist: Make dupstr be the default and part of an extensible config parm

So that we can pass more info to strlist__new() without having to change
its function signature, just adding entries to the strlist_config struct
with sensible defaults for when those fields are not specified.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-5uaaler4931i0s9sedxjquhq@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/build-id.c

@@ -291,7 +291,7 @@ int build_id_cache__list_build_ids(const char *pathname,
 	struct dirent *d;
 	int ret = 0;
 
-	list = strlist__new(true, NULL);
+	list = strlist__new(NULL, NULL);
 	dir_name = build_id_cache__dirname_from_path(pathname, false, false);
 	if (!list || !dir_name) {
 		ret = -ENOMEM;