[openssl/openssl] 4fd10c: Add an EVP demo for HMAC

[Daniel Fiala]

  Branch: refs/heads/openssl-3.0
  Home:   https://github.openssl.org/openssl/openssl
  Commit: 4fd10c123c527d75ff3f928dbc570e2b6f79c824
      https://github.openssl.org/openssl/openssl/commit/4fd10c123c527d75ff3f928dbc570e2b6f79c824
  Author: Daniel Fiala <daniel at openssl.org>
  Date:   2022-07-11 (Mon, 11 Jul 2022)

  Changed paths:
    M demos/mac/Makefile
    A demos/mac/hmac-sha512.c

  Log Message:
  -----------
  Add an EVP demo for HMAC

Fixes openssl#14109

Reviewed-by: Tomas Mraz <tomas at openssl.org>
Reviewed-by: Paul Dale <pauli at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18752)

(cherry picked from commit e269d8af79de7b0dcc1b72687eed340cc3822a9e)