CMake: Added notes pointing to the LLVM CMake documentation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@68429 91177308-0d34-0410-b5e6-96231b3b80d8

CMakeLists.txt

@@ -1,3 +1,5 @@
+# See docs/CMake.html for instructions about how to build LLVM with CMake.
+
 project(LLVM)
 cmake_minimum_required(VERSION 2.6.1)
 

cmake/README

@@ -0,0 +1 @@
+See docs/CMake.html for instructions on how to build LLVM with CMake.