Often you see a computer with a sticker on it saying "Designed for Windows 8" or "Compatible with Windows Vista". How does this actually impact the computer's hardware itself though?
Such stickers do not impact the design of the hardware per se, but rather the availibility and stability of hardware drivers for the hardware in Windows.
Typically, hardware is not designed with a particular operating system in mind. An example of this would be typical ARM SoCs (Systems on a Chip) that are capable of running, for example, iOS, Android, or Windows RT. In fact, makers of such SoCs often try to make their hardware as flexible as possible so that various device manufactures will be interested in using their chips in the design. Another example of this is Intel hardware, which runs both Windows and Mac machines.
There are, however, various issues that can arise when developing drivers for such systems. Often, such systems have bugs or quirks that only show up during the writing of drivers, and therefore device driver developers have to work around them in order for things to function perfectly.
This can be seen if you look into the Linux source code. Most major device drivers that drive devices from multiple manufacturers have to modify their behavior in order that various quirks in different devices are accounted for.
The sticker, therefore, is a statement that the drivers availible for that hardware on that operating system have been thoroughly developed and tested to work with a reasonable assurance of stability. Writers of Open Source operating systems, such as Linux, often have to wait until such quirks are published or reverse engineered in order for hardware support to be stable.