DSA_sign_setup
int DSA_sign_setup( DSA *dsa,BN_CTX *ctx_in,BIGNUM **kinvp,BIGNUM **rp);
if (!DSA_sign_setup(dsa, ctx, &kinv, &r))
LCRYPTO_ALIAS(DSA_sign_setup);
LCRYPTO_USED(DSA_sign_setup);