Fix a missing #include.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60458 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMConstantPoolValue.h b/lib/Target/ARM/ARMConstantPoolValue.h
index b5f8325..7b10565 100644
--- a/lib/Target/ARM/ARMConstantPoolValue.h
+++ b/lib/Target/ARM/ARMConstantPoolValue.h
@@ -15,6 +15,7 @@
 #define LLVM_TARGET_ARM_CONSTANTPOOLVALUE_H
 
 #include "llvm/CodeGen/MachineConstantPool.h"
+#include <ostream>
 
 namespace llvm {