Fix backward build

Author: vcsjones

src/native/libs/System.Security.Cryptography.Native/osslcompat_30.h

@@ -83,6 +83,7 @@ void EVP_MAC_free(EVP_MAC *mac);
 EVP_MD* EVP_MD_fetch(OSSL_LIB_CTX *ctx, const char *algorithm, const char *properties);
 int EVP_MD_get_size(const EVP_MD* md);
 const char *EVP_MD_get0_name(const EVP_MD *md);
+int EVP_MD_is_a(const EVP_MD *md, const char *name);
 EVP_PKEY_CTX *EVP_PKEY_CTX_new_from_name(OSSL_LIB_CTX *libctx, const char *name, const char *propquery);
 EVP_PKEY_CTX *EVP_PKEY_CTX_new_from_pkey(OSSL_LIB_CTX *libctx, EVP_PKEY *pkey, const char *propquery);
 int EVP_PKEY_CTX_set_params(EVP_PKEY_CTX *ctx, const OSSL_PARAM *params);