Add stdlib.h

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78627 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMConstantPoolValue.h b/lib/Target/ARM/ARMConstantPoolValue.h
index 37a2c80..504a71e 100644
--- a/lib/Target/ARM/ARMConstantPoolValue.h
+++ b/lib/Target/ARM/ARMConstantPoolValue.h
@@ -16,6 +16,7 @@
 
 #include "llvm/CodeGen/MachineConstantPool.h"
 #include <iosfwd>
+#include <stdlib.h>
 
 namespace llvm {