Added (libevent,tor) and modified glibc-compat

ports/glibc-compat/src/writev.c

+/* Copyright 2015 The Native Client Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file. */
+
+#include <sys/uio.h>
+#include <unistd.h> // unix(nacl) standards
+#include <errno.h>
+
+ssize_t writev(int fd,const struct iovec *iov,int iovcnt){
+  if(iovcnt < 0){
+    // #TODO(dt) add check for IOV_MAX
+    errno = EINVAL;
+    return -1;
+  }
+  ssize_t bytes_written = 0 ;
+  ssize_t bytes_supposed_to_be_written = 0 ;
+  int i;
+  for (i = 0; i < (iovcnt); i++) {
+    bytes_written +=  write(fd, iov[i].iov_base, iov[i].iov_len);
+    bytes_supposed_to_be_written += iov[i].iov_len ;
+    // #TODO(dt) add check for (max) ssize_t allowed
+    if (bytes_written != bytes_supposed_to_be_written){
+      // deliberately not setting errno here as it might override
+      // errno set by write(...)
+      return -1;
+    }
+  }
+  return bytes_written;
+}