[ORC] Add a missing #include atomic.

lhames · lhames · commit 7c848acf0a86 · 2019-09-06T20:50:00.000Z
Hopefully this will fix the bot build failures from r371245.

llvm-svn: 371255
diff --git a/llvm/unittests/ExecutionEngine/Orc/QueueChannel.h b/llvm/unittests/ExecutionEngine/Orc/QueueChannel.h
@@ -12,6 +12,7 @@
 #include "llvm/ExecutionEngine/Orc/RawByteChannel.h"
 #include "llvm/Support/Error.h"
 
+#include <atomic>
 #include <condition_variable>
 #include <queue>
 
