Build instructions on x64-windows

doc/getting-started/building-the-node-on-windows.md

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+# Development build of Cardano Node on Windows
+
+This document describes how to build a __DEVELOPMENT__ version of `cardano-node`.
+This is not a __PRODUCTION__ build!
+
+Building on `Windows` is a non trivial task.  There are various tools one needs
+to install and configure.  We recommend to use
+[chocolatey](https://chocolatey.org) (which provides the `choco` command) to
+install them.
+
+All instructrions that invoke `choco` can be done in a PowerShell with root
+previlages.  For development work we recommend installing and using `git-bash`
+(with `choco install git-bash`).
+
+## Install GHC
+
+The recommended way is to
+
+```PowerShell
+choco install --version 8.6.5 ghc
+```
+in PowerShell>
+
+We are about to transition to `ghc-8.10.2` but this version is broken on
+windows ([see](https://gitlab.haskell.org/ghc/ghc/-/issues/18550)), though
+a fix is rather easy.
+
+## Install pkg-config
+
+```PowerShell
+choco install pgkconfiglite
+```
+
+## Install vcpkg
+
+`vcpkg` is needed to install `libsodium` library, which will be the
+next step.
+
+To install it one needs `git` (which you can also install using `choco`).  Then
+follow [these
+instructions](https://github.com/microsoft/vcpkg#quick-start-windows)
+
+Now you can install `libsodium` with:
+```bash
+./vcpkg install --triplet x64-windows libsodium
+```
+
+## Write libsodium.pc file
+
+`cabal` is using `pkg-config` to find system dependencies, like `libsodium`.
+On Windows we need to write `libsodium.pc` description file in a correct
+directory.
+
+In one of the paths reported by:
+```bash
+pkg-config --variable pc_path pkg-config
+```
+create `libsodium.pc` file, which contains (but replace `VCPKG_PATH` with the
+absolute path where you put `vcpkg`, please verify that the paths below contain
+`libsodium.dll` file and headers).
+
+```
+libdir=VCPKG_PATH/installed/x64-windows/bin
+includedir=VCPKG_PATH/intsalled/x64-windows/include
+
+Name: libsodium
+Description: libsodium library
+Cflags: -I${includedir}/sodium
+Libs: -L${libdir} -llibsodium
+```
+
+Note: one cannot use `prefix=` in `libsodium.pc` file, it might be changed for
+some other directory, `pkg-config` provides a switch to use the provided
+`prefix`, but there's no way to instruct `cabal` to do so.
+
+
+## cabal configuration
+
+Now go to the directory where you cloned `cardano-node` repository and add this
+to your `cabal.project.local` file (if you don't already have it, create one):
+
+```
+max-backjump: 5000
+reorder-goals: True
+
+package cardano-crypt-praos
+  flags: -external-libsodium-vrf
+
+extra-lib-dirs: "VCPKG_PATH\\installed\\x64-windows\\bin"
+extra-include-dirs: "VCPKG_PATH\\installed\\x64-windows\\include"
+```
+
+The final part is to add `VCPKG_PATH/installed/x64-windows/bin` to `PATH`
+variable, since we are using `git-bash` this can be done with (remember
+to substitute `VCPKG_PATH` with real path):
+
+```
+export PATH="VCPKG_PATH/installed/x64-windows/bin:${PATH}"
+```
+
+Now build the node with:
+
+```bash
+cabal build --builddir /c/dist exe:cardano-node
+```
+
+And you can verify that it can run:
+```bash
+cabal run --builddir /c/dist exe:cardano-node -- run --help
+```