* On success, this function doesn't return.
* Returns -1 if the `opt_viewer` string or the default trace viewer can't be
* `exec()`.
+ *
+ * This symbol was mistakenly made public before the 2.12 release. It can't
+ * be removed (but it can be stubbed-out if necessary).
*/
int spawn_viewer(const char *trace_path, char *opt_viewer, bool opt_live_mode);