Also does absolute nothing.
The point of these things is so it's easier to test out new ports.
For example, with the Null backends and the software renderer, we
don't need to write any code to build for other platforms.
In addition, by having no platform-dependant code, this can be used
to trace crashes. For example, I was having crashes on the Wii U,
despite there being no Wii U-specific code at all - the cause turned
out to be that the executable wasn't stripped, and it had nothing to
do with the code at all.
