Merge System into Support.

llvm-svn: 120298
diff --git a/llvm/lib/Support/ToolOutputFile.cpp b/llvm/lib/Support/ToolOutputFile.cpp
index 5b5ee66..e7ca927 100644
--- a/llvm/lib/Support/ToolOutputFile.cpp
+++ b/llvm/lib/Support/ToolOutputFile.cpp
@@ -12,7 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Support/ToolOutputFile.h"
-#include "llvm/System/Signals.h"
+#include "llvm/Support/Signals.h"
 using namespace llvm;
 
 tool_output_file::CleanupInstaller::CleanupInstaller(const char *filename)