strict-aliasing-punning

From openSUSE:
```
[ 23s] I: Program is likely to break with new gcc. Try -fno-strict-aliasing.
[ 23s] W: neko strict-aliasing-punning ../libs/std/elf_update.c:62, 63, 64, 65, 66, 67, 68
[ 23s] W: neko strict-aliasing-punning ../libs/std/misc.c:81, 101
[ 23s] W: neko strict-aliasing-punning ../vm/builtins.c:370, 391, 475, 488
[ 23s] W: neko strict-aliasing-punning ../vm/elf.c:81, 84, 85, 86, 87, 114, 115, 139, 178, 179
[ 23s] W: neko strict-aliasing-punning ../vm/others.c:480, 489
```

Have to see what can we do with that...