title: Switching between packed/unpacked structs
body: <p>I have a lot of configuration data in EEPROM (4KB) which I read out in packed structures. Throughout my firmware I need to read/change these values very frequently, and performance of packed structures is not optimal, so I have a second struct which is exactly the same, only not packed. I have to copy each value one by one from the packed struct to the unpacked one, which is error-prone, because when I add a value to the packed structure I also have to remember to add it to the copy-function.</p>
  
  <p>Is there a smarter way to do this?</p>