linux-packaging-mono/external/corert/Documentation/prerequisites-for-building.md

The following pre-requisites need to be installed for building the repo:

Windows (Windows 7+)

1. Install Visual Studio 2015, including Visual C++ support. Visual Studio 2017 RC also works, but you will need to pass vs2017 as a parameter to the build script to build using this version.
2. Install CMake. We use CMake 3.3.2 but any later version should work.
3. (Windows 7 only) Install PowerShell 3.0. It's part of Windows Management Framework 3.0. Windows 8 or later comes with the right version inbox.

PowerShell also needs to be available from the PATH environment variable (it's the default). Typically it should be %SYSTEMROOT%\System32\WindowsPowerShell\v1.0.

Ubuntu (14.04)

Install basic dependency packages:

First add a new package source to be able to install clang-3.9:

echo "deb http://llvm.org/apt/trusty/ llvm-toolchain-trusty-3.9 main" | sudo tee /etc/apt/sources.list.d/llvm.list
wget -O - http://llvm.org/apt/llvm-snapshot.gpg.key | sudo apt-key add -
sudo apt-get update

sudo apt-get install cmake clang-3.9 libicu52 libunwind8

Mac OSX (10.11.5+)

1. Install Command Line Tools for XCode 8 or higher.
2. Install CMake. Launch /Applications/CMake.app/Contents/MacOS/CMake GUI. Goto "OSX App Menu -> Tools -> Install For Command Line Use" and follow the steps. CMake < 3.6 has a bug that can make --install fail. Do sudo mkdir /usr/local/bin to work around.
3. Install OpenSSL. Build tools have a dependency on OpenSSL. You can use Homebrew to install it: with Homebrew installed, run brew install openssl followed by ln -s /usr/local/opt/openssl/lib/libcrypto.1.0.0.dylib /usr/local/lib/, followed by ln -s /usr/local/opt/openssl/lib/libssl.1.0.0.dylib /usr/local/lib/.