diff --git a/Makefile b/Makefile
index 2183a5b24fd..319bdcd0fba 100644
--- a/Makefile
+++ b/Makefile
@@ -66,7 +66,8 @@ ifeq ($(MAKECMDGOALS),tools-only)
 endif
 
 ifeq ($(MAKECMDGOALS),install-clang)
-  DIRS := tools/clang/tools/driver tools/clang/lib/Headers tools/clang/docs
+  DIRS := tools/clang/tools/driver tools/clang/lib/Headers \
+          tools/clang/lib/Runtime tools/clang/docs
   OPTIONAL_DIRS :=
   NO_INSTALL = 1
 endif