Fix compile failures with g++-4.3.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45781 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/System/Path.cpp b/lib/System/Path.cpp
index 1449597..6f0667f 100644
--- a/lib/System/Path.cpp
+++ b/lib/System/Path.cpp
@@ -14,6 +14,7 @@
 #include "llvm/System/Path.h"
 #include "llvm/Config/config.h"
 #include <cassert>
+#include <cstring>
 #include <ostream>
 using namespace llvm;
 using namespace sys;