Select an RFC 5114 DHX (X9.42 DH) named parameter set on a keygen/paramgen context.
Declared in <openssl/dh.h>
<openssl/dh.h>
int EVP_PKEY_CTX_set_dhx_rfc5114( EVP_PKEY_CTX* ctx, int gen);
1 on success, or a non-positive value on failure.