CMake: Add FileUpdate to the build.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121386 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2d1f66b..aec7d65 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -335,6 +335,7 @@
 add_subdirectory(lib/Object)
 
 add_subdirectory(utils/FileCheck)
+add_subdirectory(utils/FileUpdate)
 add_subdirectory(utils/count)
 add_subdirectory(utils/not)
 add_subdirectory(utils/llvm-lit)