fixed the ffmpeg build size

libs/FFmpeg/include/libavutil/time.h

@@ -28,6 +28,21 @@
  */
 int64_t av_gettime(void);
 
+/**
+ * Get the current time in microseconds since some unspecified starting point.
+ * On platforms that support it, the time comes from a monotonic clock
+ * This property makes this time source ideal for measuring relative time.
+ * If a monotonic clock is not available on the targeted platform, the
+ * implementation fallsback on using av_gettime().
+ */
+int64_t av_gettime_relative(void);
+
+/**
+ * Indicates with a boolean result if the av_gettime_relative() time source
+ * is monotonic.
+ */
+int av_gettime_relative_is_monotonic(void);
+
 /**
  * Sleep for a period of time.  Although the duration is expressed in
  * microseconds, the actual delay may be rounded to the precision of the