Set error callback helper

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

core/dive.h

@@ -698,6 +698,7 @@ extern "C" {
 extern int report_error(const char *fmt, ...);
 extern void report_message(const char *msg);
 extern const char *get_error_string(void);
+extern void set_error_cb(void(*cb)(void));
 
 extern struct dive *find_dive_including(timestamp_t when);
 extern bool dive_within_time_range(struct dive *dive, timestamp_t when, timestamp_t offset);