Use clock_gettime instead of gettimeofday, it's more effiency on low …

…power system

Add def for mac(They don't support clock_gettime)

Fix my mistake

Fix my mistake 2

Source/Core/Common/Timer.cpp

@@ -25,10 +25,14 @@ u32 Timer::GetTimeMs()
 {
 #ifdef _WIN32
 	return timeGetTime();
-#else
+#elif defined __APPLE__
 	struct timeval t;
 	(void)gettimeofday(&t, nullptr);
 	return ((u32)(t.tv_sec * 1000 + t.tv_usec / 1000));
+#else
+	struct timespec t;
+	(void)clock_gettime(CLOCK_MONOTONIC, &t);
+	return ((u32)(t.tv_sec * 1000 + t.tv_nsec / 1000000));
 #endif
 }
 
@@ -48,10 +52,14 @@ u64 Timer::GetTimeUs()
 	static double freq = GetFreq();
 	QueryPerformanceCounter(&time);
 	return u64(double(time.QuadPart) * freq);
-#else
+#elif defined __APPLE__
 	struct timeval t;
 	(void)gettimeofday(&t, nullptr);
 	return ((u64)(t.tv_sec * 1000000 + t.tv_usec));
+#else
+	struct timespec t;
+	(void)clock_gettime(CLOCK_MONOTONIC, &t);
+	return ((u64)(t.tv_sec * 1000000 + t.tv_nsec / 1000));
 #endif
 }
 
@@ -205,10 +213,14 @@ std::string Timer::GetTimeFormatted()
 	struct timeb tp;
 	(void)::ftime(&tp);
 	return StringFromFormat("%s:%03i", tmp, tp.millitm);
-#else
+#elif defined __APPLE__
 	struct timeval t;
 	(void)gettimeofday(&t, nullptr);
 	return StringFromFormat("%s:%03d", tmp, (int)(t.tv_usec / 1000));
+#else
+	struct timespec t;
+	(void)clock_gettime(CLOCK_MONOTONIC, &t);
+	return StringFromFormat("%s:%03d", tmp, (int)(t.tv_nsec / 1000000));
 #endif
 }
 
@@ -219,9 +231,12 @@ double Timer::GetDoubleTime()
 #ifdef _WIN32
 	struct timeb tp;
 	(void)::ftime(&tp);
-#else
+#elif defined __APPLE__
 	struct timeval t;
 	(void)gettimeofday(&t, nullptr);
+#else
+	struct timespec t;
+	(void)clock_gettime(CLOCK_MONOTONIC, &t);
 #endif
 	// Get continuous timestamp
 	u64 TmpSeconds = Common::Timer::GetTimeSinceJan1970();
@@ -236,8 +251,10 @@ double Timer::GetDoubleTime()
 	u32 Seconds = (u32)TmpSeconds;
 #ifdef _WIN32
 	double ms = tp.millitm / 1000.0 / 1000.0;
-#else
+#elif defined __APPLE__
 	double ms = t.tv_usec / 1000000.0;
+#else
+	double ms = t.tv_nsec / 1000000000.0;
 #endif
 	double TmpTime = Seconds + ms;