Make sure install Clang headers when building clang-cc

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@74163 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/clang-cc/CMakeLists.txt b/tools/clang-cc/CMakeLists.txt
index ec2ea3d..e224d40 100644
--- a/tools/clang-cc/CMakeLists.txt
+++ b/tools/clang-cc/CMakeLists.txt
@@ -24,3 +24,4 @@
 add_clang_executable(clang-cc
   clang-cc.cpp
   )
+add_dependencies(clang-cc clang-headers)