readd seconds stuff

src/os/os_unix.c

@@ -10,3 +10,16 @@ fn os_date_t os_local_time_now(void) {
     result.year = lt->tm_year;
     return result;
 }
+
+fn u64 os_get_microseconds(void) {
+    struct timespec t;
+    clock_gettime(CLOCK_MONOTONIC, &t);
+    u64 result = t.tv_sec*million(1) + (t.tv_nsec/thousand(1));
+    return result;
+}
+
+fn f64 os_get_milliseconds(void) {
+    u64 micros = os_get_microseconds();
+    f64 result = (f64)micros / 1000.0;
+    return result;
+}