Updated instructions for installing cmake to newer version

The available version of cmake for Ubuntu 12.04 is too old.
The PPA listed does not currently work so the official
cmake webisite is a more reliable source to get cmake.

Signed-off-by: Mark Charlebois <charlebm@gmail.com>

Makefile

@@ -44,10 +44,18 @@ ifneq ($(CMAKE_VER),0)
     $(warning Not a valid CMake version or CMake not installed.)
     $(warning On Ubuntu, install or upgrade via:)
     $(warning )
+    $(warning 3rd party PPA:)
     $(warning sudo add-apt-repository ppa:george-edison55/cmake-3.x -y)
     $(warning sudo apt-get update)
     $(warning sudo apt-get install cmake)
     $(warning )
+    $(warning Official website:)
+    $(warning wget https://cmake.org/files/v3.3/cmake-3.3.2-Linux-x86_64.sh)
+    $(warning chmod +x cmake-3.3.2-Linux-x86_64.sh)
+    $(warning sudo mkdir /opt/cmake-3.3.2)
+    $(warning sudo ./cmake-3.3.2-Linux-x86_64.sh --prefix=/opt/cmake-3.3.2 --exclude-subdir)
+    $(warning export PATH=/opt/cmake-3.3.2/bin:$$PATH)
+    $(warning )
     $(error Fatal)
 endif