refactor - reduce CTFE memory consumption pt 1

Currently, CTFE allocates memory for every step in its computation. This can result in an enormous amount allocated. This is the first step towards using stack memory instead.
You could rewrite:
```
new(&b) S();
```
as:
```
S s();
memcpy(&b,&s,sizeof(S));
```
for your translation. I don't want to do it in the C++ code, as it is an extra copy step.