fix: use clock instead of timeofday

src/timer.c

@@ -1,4 +1,4 @@
-#include <sys/time.h>
+#include <time.h>
 
 #include "types.h"
 
@@ -7,8 +7,7 @@
 void timer_init(Timer *timer, const unsigned int target) {
   timer->counter = 0;
   timer->target = target;
-
-  gettimeofday(&timer->start, NULL);
+  timer->start = clock();
 }
 
 bool timer_inc(Timer *timer) {
@@ -17,14 +16,13 @@ bool timer_inc(Timer *timer) {
 }
 
 double timer_reset(Timer *timer) {
-  struct timeval stop;
+  clock_t stop;
   double secs;
   double per_secs;
 
-  gettimeofday(&stop, NULL);
+  stop = clock();
 
-  secs = (double)(stop.tv_usec - timer->start.tv_usec) / 1000000 +
-         (double)(stop.tv_sec - timer->start.tv_sec);
+  secs = (double)(stop - timer->start) / CLOCKS_PER_SEC;
   per_secs = (double)timer->counter / secs;
 
   timer->start = stop;