[NaCl SDK} Add EventListener and EventEmitter to support epoll.

native_client_sdk/src/libraries/nacl_io/kernel_wrap_newlib.cc

Index: native_client_sdk/src/libraries/nacl_io/kernel_wrap_newlib.cc
diff --git a/native_client_sdk/src/libraries/nacl_io/kernel_wrap_newlib.cc b/native_client_sdk/src/libraries/nacl_io/kernel_wrap_newlib.cc
index af314921cf86717f54e48913cbe1ff4724c7cd33..ff5896fda46bcd606695f2eabbc111976ff07bf2 100644
--- a/native_client_sdk/src/libraries/nacl_io/kernel_wrap_newlib.cc
+++ b/native_client_sdk/src/libraries/nacl_io/kernel_wrap_newlib.cc
@@ -14,6 +14,7 @@
 #include <irt.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
+#include <sys/time.h>
 #include "nacl_io/kernel_intercept.h"
 
 EXTERN_C_BEGIN
@@ -261,6 +262,11 @@ int _real_write(int fd, const void *buf, size_t count, size_t *nwrote) {
   return REAL(write)(fd, buf, count, nwrote);
 }
 
+uint64_t usec_since_epoch() {
+  struct timeval tv;
+  gettimeofday(&tv, NULL);
+  return tv.tv_usec + (tv.tv_sec * 1000000);
+}
 
 void kernel_wrap_init() {
   static bool wrapped = false;