sethvalue
sethvalue(L, L->top, t);
sethvalue(L, L->top, mt);
sethvalue(L, L->top, uvalue(o)->env);
sethvalue(fs->ls->L, &k, fs->h);
sethvalue(L, L->top, t); /* push it on stack */
#define sethvalue2s sethvalue
sethvalue(L, &g->l_registry, registry);
sethvalue(L, &mt, luaH_new(L));
sethvalue(L, ra, t);