Add missing include.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17799 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/System/Path.cpp b/lib/System/Path.cpp
index d582759..a530f28 100644
--- a/lib/System/Path.cpp
+++ b/lib/System/Path.cpp
@@ -12,6 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/System/Path.h"
+#include <cassert>
 
 namespace llvm {
 using namespace sys;