[Driver] Add missed include header.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@214950 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Driver/Multilib.h b/include/clang/Driver/Multilib.h
index d19097b0a7def3651cea53b53ebaf67c85d14778..0b64456d22aaa1ea82f0a5b67b785370712a4546 100644 (file)
--- a/include/clang/Driver/Multilib.h
+++ b/include/clang/Driver/Multilib.h
@@ -13,6 +13,8 @@
 #include "clang/Basic/LLVM.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/Option/Option.h"
+
+#include <functional>
 #include <string>
 #include <vector>