PVS-Studio warning V597 for tor-project

int
crypto_pk_private_sign_digest(....)
{
  char digest[DIGEST_LEN];
  ....
  memset(digest, 0, sizeof(digest));
  return r;
}

This suspicious code was found in tor-project project by PVS-Studio static code analyzer.
Warning message is:
V597 The compiler could delete the 'memset' function call, which is used to flush 'digest' buffer. The RtlSecureZeroMemory() function should be used to erase the private data. crypto.c 1015

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/