Build the clang headers.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@47834 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Makefile b/Makefile
index e7b647f..10350a8 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,5 @@
 LEVEL = ../..
-DIRS := Basic Lex Parse AST Sema CodeGen Analysis Rewrite Driver
+DIRS := Headers Basic Lex Parse AST Sema CodeGen Analysis Rewrite Driver
 
 include $(LEVEL)/Makefile.common