Fix build break on OS X from cleanup check-in.

I'll track down why our CI is not sending out emails on build breaks.

llvm-svn: 251522
diff --git a/lldb/source/Core/IOHandler.cpp b/lldb/source/Core/IOHandler.cpp
index 4280e8f..cf290e9 100644
--- a/lldb/source/Core/IOHandler.cpp
+++ b/lldb/source/Core/IOHandler.cpp
@@ -14,6 +14,9 @@
 #endif
 
 // C++ Includes
+#if defined(__APPLE__)
+#include <deque>
+#endif
 #include <string>
 
 // Other libraries and framework includes
@@ -36,6 +39,8 @@
 #include "lldb/Target/RegisterContext.h"
 #include "lldb/Target/ThreadPlan.h"
 
+
+
 using namespace lldb;
 using namespace lldb_private;