Fixup broken doc link.  Patch by Sean Silva <silvas@purdue.edu>.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160082 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/CMake.rst b/docs/CMake.rst
index 7e16162..e1761c5 100644
--- a/docs/CMake.rst
+++ b/docs/CMake.rst
@@ -1,4 +1,4 @@
-.. _cmake:
+.. _building-with-cmake:
 
 ========================
 Building LLVM with CMake