disbale CUDA backend for cryptonight_v8

xmrstak/backend/nvidia/minethd.cpp

@@ -144,6 +144,13 @@ std::vector<iBackend*>* minethd::thread_starter(uint32_t threadOffset, miner_wor
 {
 	std::vector<iBackend*>* pvThreads = new std::vector<iBackend*>();
 
+	auto miner_algo = ::jconf::inst()->GetCurrentCoinSelection().GetDescription(1).GetMiningAlgoRoot();
+	if(miner_algo == cryptonight_monero_v8)
+	{
+		std::cerr<<"ERROR: The CUDA backend is currently not supporting cryptonight_v8, please use `--openCLVendor NVIDIA` instead."<<std::endl;
+		return pvThreads;
+	}
+
 	if(!configEditor::file_exist(params::inst().configFileNVIDIA))
 	{
 		autoAdjust adjust;