Function nginx::BN_mod_exp_mont_consttime

pub unsafe extern "C" fn BN_mod_exp_mont_consttime(
    rr: *mut BIGNUM, 
    a: *const BIGNUM, 
    p: *const BIGNUM, 
    m: *const BIGNUM, 
    ctx: *mut BN_CTX, 
    in_mont: *mut BN_MONT_CTX
) -> c_int