Update docs for removal of Ubuntu 14.04 as a supported platform

Author: hughbe

README.md

@@ -61,12 +61,7 @@ For Ubuntu, you'll need the following development dependencies:
 **Note:** LLDB currently requires at least `swig-1.3.40` but will successfully build
 with version 2 shipped with Ubuntu.
 
-If you are building on Ubuntu 14.04 LTS, you'll need to upgrade your clang
-compiler for C++14 support and create a symlink:
-
-    sudo apt-get install clang-3.6
-    sudo update-alternatives --install /usr/bin/clang clang /usr/bin/clang-3.6 100
-    sudo update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-3.6 100
+Ubuntu 14.04 LTS is no longer supported. Unsupported build instructions for Ubuntu 14.04 LTS can be found [here](docs/Ubuntu14.md)
 
 ### Getting Sources for Swift and Related Projects
 

docs/Ubuntu14.md

@@ -0,0 +1,27 @@
+# Getting Started with Swift on Ubunutu 14.04
+
+The Swift project no longer officially supports Ubuntu 14.04 as a build platform.
+It is highly recommended to upgrade to Ubuntu 16.04 or higher in order to have the best experience building and running the project.
+
+If you cannot upgrade Ubuntu to a more up to date version, you should do follow these steps before checking out and build the Swift source code. These are not guaranteed to work in the future, and may break or be unreliable.
+
+## Upgrade Clang
+You'll need to upgrade your clang compiler for C++14 support and create a symlink. The minimum required version of clang may change, and may not be available on Ubuntu 14.04 in the future.
+```bash
+sudo apt-get install clang-3.6
+sudo update-alternatives --install /usr/bin/clang clang /usr/bin/clang-3.6 100
+sudo update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-3.6 100
+```
+
+## Upgrade CMake
+You'll need to upgrade your cmake toolchain to a supported version by building a local copy. The minimum required version of cmake may change, and may not be available on Ubuntu 14.04 in the future.</p>
+```bash
+wget http://www.cmake.org/files/v3.5/cmake-3.5.2.tar.gz
+tar xf cmake-3.5.2.tar.gz
+cd cmake-3.5.2
+./configure
+make
+sudo make install
+sudo update-alternatives --install /usr/bin/cmake cmake /usr/local/bin/cmake 1 --force
+cmake --version # This should print 3.5.2
+```