zxing-cpp: strip to core library only (remove tests/wrappers/examples/docs); .gitignore: fix /core to allow zxing-cpp/core/ dir

tools/chatgui/zxing-cpp/core/src/ZXConfig.h

@@ -0,0 +1,17 @@
+/*
+* Copyright 2018 Axel Waggershauser
+*/
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+// Thread local or static memory may be used to reduce the number of (re-)allocations of temporary variables
+// in e.g. the HistogramBinarizer. The default is thread_local, which is the best option for performance and safety in most cases. If
+// your platform doesn't support thread_local, you can switch to static, but be aware that this makes the code not thread safe.
+// For Windows in Visual Studio 2019 on Intel 64-bit using thread_local causes a dependency to VCRUNTIME140_1.dll, so you need 2019
+// runtime DLLs instead of only 2015 version.
+#define ZX_THREAD_LOCAL thread_local // '' (nothing), 'thread_local' or 'static'
+
+// The Galois Field abstractions used in Reed-Solomon error correction code use more memory than required to improve performance (20% - 100%).
+// If RAM is scarce, you can define LIBRSCPP_SAVE_MEMORY to reduce memory usage. The effect is a few kB big.
+// #define LIBRSCPP_SAVE_MEMORY