Mitigate compilation issue.

std::bad_alloc is defined in <new>
--- a/clients/include/host_alloc.hpp
+++ b/clients/include/host_alloc.hpp
@@ -22,6 +22,8 @@
 
 #pragma once
 
+#include <new>
+
 //!
 //! @brief Host free memory w/o swap.  Returns kB or -1 if unknown.
 //!