The following code has a runtime of over 60 seconds.

#include <time.h>
#include <stdint.h>

int main() {
    time_t tm = INT64_MAX;
    localtime(&tm);
}

You might ask "BertalanD, who in their right mind would write code like this?" Apparently a bunch of ports that use autotools (like bash), as they use this to determine if our mktime implementation works correctly. They actually have a 60-second timeout, but they actually run this test multiple times with slightly different values...

The reason for this slowness is that we use a linear-time algorithm to determine how many years have passed since the Unix epoch.