Add optional CMake build for Clang examples, patch by Kovarththanan Rajaratnam.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@89078 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7f4ab33..9e84d94 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -94,6 +94,11 @@
 
 add_definitions( -D_GNU_SOURCE )
 
+option(CLANG_BUILD_EXAMPLES "Build CLANG example programs." OFF)
+if(CLANG_BUILD_EXAMPLES)
+  add_subdirectory(examples)
+endif ()
+
 add_subdirectory(include)
 add_subdirectory(lib)
 add_subdirectory(tools)