It is reinterpreting a pointer to DC_ATTR into a pointer to void* and then storing an address at that location to make it part of a linked list.
Code:
#include <stdio.h>
#include <stdlib.h>
#define prn(x) printf(#x ": %p\n", (void*)x)
struct Stuff {
int a, b, c, d;
};
int main() {
void *list = NULL;
struct Stuff *a = malloc(sizeof *a);
*(void**)a = list;
list = a;
struct Stuff *b = malloc(sizeof *b);
*(void**)b = list;
list = b;
prn(a);
prn(b);
prn(list);
struct Stuff *x = list;
list = *(void**)list;
x->a = 1;
x->b = 2;
prn(list);
return 0;
}