OPENSSL_ALGO_DSS1
      (int)
     OPENSSL_ALGO_SHA1
      (int)
     OPENSSL_ALGO_SHA224
      (int)
     OPENSSL_ALGO_SHA256
      (int)
     OPENSSL_ALGO_SHA384
      (int)
     OPENSSL_ALGO_SHA512
      (int)
     OPENSSL_ALGO_RMD160
      (int)
     OPENSSL_ALGO_MD5
      (int)
     OPENSSL_ALGO_MD4
      (int)
     OPENSSL_ALGO_MD2
      (int)
     -DHAVE_OPENSSL_MD2_H CFLAG when compiling PHP,
       and enable-md2 when compiling OpenSSL 1.0.0+.