Upgrade libevent to release-2.1.10-stable

Test: None
Change-Id: I24e4275a07a6dcdd932056c7893a6aabdd786b8a
diff --git a/time-internal.h b/time-internal.h
index 2c584fa..e79e6a5 100644
--- a/time-internal.h
+++ b/time-internal.h
@@ -54,6 +54,7 @@
 #endif
 
 long evutil_tv_to_msec_(const struct timeval *tv);
+EVENT2_EXPORT_SYMBOL
 void evutil_usleep_(const struct timeval *tv);
 
 #ifdef _WIN32
@@ -86,8 +87,10 @@
 	struct timeval last_time;
 };
 
+EVENT2_EXPORT_SYMBOL
 int evutil_configure_monotonic_time_(struct evutil_monotonic_timer *mt,
     int flags);
+EVENT2_EXPORT_SYMBOL
 int evutil_gettime_monotonic_(struct evutil_monotonic_timer *mt, struct timeval *tv);