Fixed weird struct problem from downs, see mini/compile_structs1.d Rewrote DtoIndexStruct/Class , the old implementation were way too complex for what we really need now - since the DotVar changes.

void main()
{
    int* e = __errno_location();
    printf("&errno = %p\n", e);
    printf("errno = %d\n", *e);
}

extern(C):
int* __errno_location();
int printf(char*,...);