Get rid of the flaky time_lock and use the thread safe localtime_r instead.

main.c

@@ -153,7 +153,6 @@ static int work_thr_id;
 int longpoll_thr_id;
 static int stage_thr_id;
 struct work_restart *work_restart = NULL;
-pthread_mutex_t time_lock;
 static pthread_mutex_t hash_lock;
 static pthread_mutex_t qd_lock;
 static pthread_mutex_t stgd_lock;
@@ -1740,8 +1739,6 @@ int main (int argc, char *argv[])
 	unsigned int i, j = 0;
 	char name[32];
 
-	if (unlikely(pthread_mutex_init(&time_lock, NULL)))
-		return 1;
 	if (unlikely(pthread_mutex_init(&hash_lock, NULL)))
 		return 1;
 	if (unlikely(pthread_mutex_init(&qd_lock, NULL)))

miner.h

@@ -226,7 +226,6 @@ struct work_restart {
 	char			padding[128 - sizeof(unsigned long)];
 };
 
-extern pthread_mutex_t time_lock;
 extern int hw_errors;
 extern bool use_syslog;
 extern struct thr_info *thr_info;

util.c

@@ -71,14 +71,11 @@ void vapplog(int prio, const char *fmt, va_list ap)
 		char *f;
 		int len;
 		struct timeval tv = { };
-		struct tm tm, *tm_p;
+		struct tm tm;
 
 		gettimeofday(&tv, NULL);
 
-		pthread_mutex_lock(&time_lock);
-		tm_p = localtime(&tv.tv_sec);
-		memcpy(&tm, tm_p, sizeof(tm));
-		pthread_mutex_unlock(&time_lock);
+		localtime_r(&tv.tv_sec, &tm);
 
 		len = 40 + strlen(fmt) + 2;
 		f = alloca(len);