initialize sse state in new tasks (seems to hang later on fxrstor still)

src/arch/x86/task.c

@@ -175,6 +175,7 @@ struct Task *new_ktask(void(*fn), char *name) {
     new->frame.ip = (uint64_t) fn;
     new->frame.cs = GDTSEL(gdt_code);
     new->frame.ss = GDTSEL(gdt_data);
+    __builtin_ia32_fxsave64((void *) (((uintptr_t) (new->frame.ssestate) + 32) & 0xFFFFFFFFFFFFFFF0));
     new->frame.flags = flags();
     new->frame.guard = IDT_GUARD;
     new->addressSpace = KERN_AddressSpace;