Question about linking `OpenSSL`

[hybcloud]

In configure.ac there are such codes to check if EVP_MC_CTX_copy is presented in the OpenSSL library.

AC_MSG_CHECKING([whether to enable use of openssl crypto library])
AC_ARG_ENABLE([openssl],
	AS_HELP_STRING([--disable-openssl],[disable to omit openssl crypto library]))
AH_TEMPLATE([USE_OPENSSL],
[Undefine if you do not want to use openssl crypto library.  By default this is defined.])
if test x"$enable_openssl" != x"no"; then
    if test x"$ac_cv_header_openssl_md4_h" = x"yes" && test x"$ac_cv_header_openssl_md5_h" = x"yes"; then
      AC_MSG_RESULT(yes)
      AC_SEARCH_LIBS(EVP_MD_CTX_copy, crypto,
          [AC_DEFINE(USE_OPENSSL)
	   enable_openssl=yes],
          [err_msg="$err_msg$nl- Failed to find EVP_MD_CTX_copy function in openssl crypto lib.";
	   no_lib="$no_lib openssl"])
    else
        AC_MSG_RESULT(no)
	err_msg="$err_msg$nl- Failed to find openssl/md4.h and openssl/md5.h for openssl crypto lib support."
	no_lib="$no_lib openssl"
    fi
    if test x"$enable_md5_asm" != x"yes"; then
	enable_md5_asm=no
    fi
else
    AC_MSG_RESULT(no)
fi

However, it seems that such function and EVP_MC_CTX_create (which is actually used in rsync) is no longer available in OpenSSL 3.0 and above?

Could anyone please advise on the currently recommended solution?

• Should I use --disable-openssl during configuration?
• Or should I link to the discontinued OpenSSL 1.1.1?
• Or perhaps I might have misunderstood this issue?