Check result of malloc in Poly_string_to_C_alloc and Poly_string_to_U_alloc Malloc may return zero if there is insufficient space.  Check the result and return NULL in that case.
Check result of malloc in Poly_string_to_C_alloc and Poly_string_to_U_alloc
Malloc may return zero if there is insufficient space.  Check the result and
return NULL in that case.

mn200/polyml,polyml/polyml,polyml/polyml,dcjm/polyml,mn200/polyml,mn200/polyml,mn200/polyml,dcjm/polyml,polyml/polyml,dcjm/polyml,polyml/polyml,dcjm/polyml