Add Building instructions

Building.md

@@ -0,0 +1,77 @@
+# Building
+
+## Setting up your development environment
+
+Before building Rack, you must install build dependencies provided by your system's package manager.
+Rack's own dependencies (GLEW, glfw, etc) do not need to be installed on your system, since specific versions are compiled locally during the build process.
+However, you need proper tools to build Rack and these dependencies.
+
+### Mac
+
+Install [Xcode](https://developer.apple.com/xcode/).
+Using [Homebrew](https://brew.sh/), install the build dependencies.
+```
+brew install git wget cmake autoconf automake libtool
+```
+
+### Windows
+
+Install [MSYS2](http://www.msys2.org/) and launch the MinGW 64-bit shell (not the default MSYS shell).
+```
+pacman -S git wget make tar unzip zip mingw-w64-x86_64-gcc mingw-w64-x86_64-cmake autoconf automake mingw-w64-x86_64-libtool
+```
+
+### Linux
+
+On Ubuntu 16.04:
+```
+sudo apt install git curl cmake libx11-dev libglu1-mesa-dev libxrandr-dev libxinerama-dev libxcursor-dev libxi-dev zlib1g-dev libasound2-dev libgtk2.0-dev libjack-jackd2-dev
+```
+
+On Arch Linux:
+```
+pacman -S git wget gcc make cmake tar unzip zip curl
+```
+
+## Building Rack
+
+*If the build fails for you, please report the issue with a detailed error message to help the portability of Rack.*
+
+Clone this repository with `git clone https://github.com/VCVRack/Rack.git` and `cd Rack`.
+Make sure there are no spaces in your absolute path, as this breaks many build systems.
+
+Clone submodules.
+
+	git submodule update --init --recursive
+
+Build dependencies locally.
+You may add `-j$(nproc)` to your make commands to parallelize builds across all CPU cores.
+
+	make dep
+
+Build Rack.
+
+	make
+
+Run Rack.
+
+	make run
+
+## Building Rack plugins
+
+Be sure to check out and build the version of Rack you wish to build your plugins against.
+
+It is recommended to download plugins to Rack's `plugins/` directory, e.g.
+
+	cd plugins
+	git clone https://github.com/VCVRack/Fundamental.git
+
+Clone the git repo's submodules.
+
+	cd Fundamental
+	git submodule update --init --recursive
+
+Build the plugin.
+
+	make dep
+	make

PluginDevelopmentTutorial.md

@@ -3,8 +3,8 @@
 ## Prerequisites
 
 - Familiarity with C++ is required.
-- Follow the [Setting up your development environment](https://github.com/VCVRack/Rack#setting-up-your-development-environment) section of the Rack README.
-- If you would like to build Rack from source, continue to the [Building](https://github.com/VCVRack/Rack#building) section of the Rack README.
+- [Set up your development environment](Building.html#setting-up-your-development-environment).
+- If you would like to build Rack from source, follow [Building Rack](Building.html#building-rack).
 - If you would like to save time, you may skip building Rack and use the [Rack SDK](https://github.com/VCVRack/Rack/issues/258#issuecomment-376293898) instead. You can then run your plugin with an official build of Rack.
 
 ## Template Plugin