Clean up some suspicious code. There's no guarantee a constant of integer type is a ConstantInt, so it's not safe to just cast<> these to ConstantInt. (It could be a constant expression, for example) The code is shorter this way too :).

module internal.mem;

extern(C):

void* realloc(void*,size_t);
void free(void*);

void* _d_realloc(void* ptr, size_t n)
{
    return realloc(ptr, n);
}

void _d_free(void* ptr)
{
    free(ptr);
}