Merge System into Support.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120298 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/Debug.cpp b/lib/Support/Debug.cpp
index 7f48f8a..9fdb12e 100644
--- a/lib/Support/Debug.cpp
+++ b/lib/Support/Debug.cpp
@@ -26,7 +26,7 @@
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/circular_raw_ostream.h"
-#include "llvm/System/Signals.h"
+#include "llvm/Support/Signals.h"
 
 using namespace llvm;