int caldav_time_range_filter_matches(icalcomponent *cal, char *start_str, char *end_str) {
struct icaltimetype start = icaltime_from_string(start_str);
int caldav_time_range_filter_matches(icalcomponent *cal, char *start_str, char *end_str) {
struct icaltimetype start = icaltime_from_string(start_str);