[commit: ghc] wip/nfs-locking: Add docs for how to compile on Windows, with a list of complete instructions (3dcbe7a)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : wip/nfs-locking
Link       : http://ghc.haskell.org/trac/ghc/changeset/3dcbe7a62e7ad62016456000c925d6493e509a2e/ghc

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commit 3dcbe7a62e7ad62016456000c925d6493e509a2e
Author: Neil Mitchell <ndmitchell at gmail.com>
Date:   Thu Mar 3 20:52:50 2016 +0000

    Add docs for how to compile on Windows, with a list of complete instructions


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+# Compiling on Windows
+
+Here are a list of instructions to compile GHC, from source, on Windows. I tested these instructions on a clean machine using the [free Windows 10 VirtualBox image](https://dev.windows.com/en-us/microsoft-edge/tools/vms/windows/) (I bumped the VM CPUs to 4, and RAM to 4096Mb). These instructions are not currently the official GHC building instructions, but might be simpler and more robust than those.
+
+The first step is to [install Stack](https://www.stackage.org/stack/windows-x86_64-installer) (I just accepted all the defaults), then open a command prompt and run:
+
+	stack setup
+	stack install happy alex
+	stack exec -- pacman -S gcc binutils git automake-wrapper tar make patch autoconf --noconfirm
+	stack exec -- git clone --recursive git://git.haskell.org/ghc.git
+	cd ghc
+	stack exec -- git clone git://github.com/snowleopard/shaking-up-ghc shake-build
+	stack build --stack-yaml=shake-build/stack.yaml --only-dependencies
+	stack exec -- perl boot
+	stack exec -- bash configure --enable-tarballs-autodownload
+	stack exec --stack-yaml=shake-build/stack.yaml -- shake-build/build.bat -j
+
+The entire process should take about an hour.
+
+#### Future ideas
+
+Here are some alternatives that have been considered, but not yet tested. Use the instructions above.
+
+* Use `shake-build/build.bat --setup` to replace `boot` and `configure`.
+* The `pacman` install of `gcc` is probably not necessary, but it does pull in a lot of tools, some of which probably are necessary. Ideally thin the list down.
+* Can Happy/Alex be installed by adding them as tool dependencies to the Stack file?