The EVP_MD_CTX_create() and EVP_MD_CTX_destroy() functions were renamed to EVP_MD_CTX_new() and EVP_MD_CTX_free() in OpenSSL 1.1.0, respectively. These functions are used by the digest converter, introduced by the commit 8e36651ed ("MINOR: sample: Add digest and hmac converters"). So for prior versions of openssl, macros are used to fallback on old functions. This patch must only be backported if the commit 8e36651ed is backported too.