Added generic Argon2 implementation (conflicts with RandomX).

src/3rdparty/argon2/README.md

@@ -0,0 +1,58 @@
+# Argon2 [![Build Status](https://travis-ci.org/WOnder93/argon2.svg?branch=master)](https://travis-ci.org/WOnder93/argon2)
+A multi-arch library implementing the Argon2 password hashing algorithm.
+
+This project is based on the [original source code](https://github.com/P-H-C/phc-winner-argon2) by the Argon2 authors. The goal of this project is to provide efficient Argon2 implementations for various HW architectures (x86, SSE, ARM, PowerPC, ...).
+
+For the x86_64 architecture, the library implements a simple CPU dispatch which automatically selects the best implementation based on CPU flags and quick benchmarks.
+
+# Building
+## Using GNU autotools
+
+To prepare the build environment, run:
+```bash
+autoreconf -i
+./configure
+```
+
+After that, just run `make` to build the library.
+
+### Running tests
+After configuring the build environment, run `make check` to run the tests.
+
+### Architecture options
+You can specify the target architecture by passing the `--host=...` flag to `./configure`.
+
+Supported architectures:
+ * `x86_64` – 64-bit x86 architecture
+ * `generic` – use generic C impementation
+
+## Using CMake
+
+To prepare the build environment, run:
+```bash
+cmake -DCMAKE_BUILD_TYPE=Release .
+```
+
+Then you can run `make` to build the library.
+
+## Using QMake/Qt Creator
+A [QMake](http://doc.qt.io/qt-4.8/qmake-manual.html) project is also available in the `qmake` directory. You can open it in the [Qt Creator IDE](http://wiki.qt.io/Category:Tools::QtCreator) or build it from terminal:
+```bash
+cd qmake
+# see table below for the list of possible ARCH and CONFIG values
+qmake ARCH=... CONFIG+=...
+make
+```
+
+### Architecture options
+For QMake builds you can configure support for different architectures. Use the `ARCH` variable to choose the architecture and the `CONFIG` variable to set additional options.
+
+Supported architectures:
+ * `x86_64` – 64-bit x86 architecture
+   * QMake config flags:
+     * `USE_SSE2` – use SSE2 instructions
+     * `USE_SSSE3` – use SSSE3 instructions
+     * `USE_XOP` – use XOP instructions
+     * `USE_AVX2` – use AVX2 instructions
+     * `USE_AVX512F` – use AVX-512F instructions
+ * `generic` – use generic C impementation