But the GPL applies to the driver they released, not some hypothetical driver that you or somebody else might create in the future. You're already going to have

But the GPL applies to the driver they released, not some hypothetical driver that you or somebody else might create in the future. You're already going to have to rewrite it all in this proposed alternative language... this header is the least of your worries. Strikes me that AMD have supplied everything required: all the driver code in the preferred form for modification of the driver, i.e., a bunch of C files. Some of these C files are a big long list of slightly opaque magic number defines that relate to the hardware, perhaps generated by some unreleased tool, who can say - it's all speculation at this point - but that's OK! The hardware is not the bit you're going to modify. As far as the people modifying the drivers are concerned, those numbers are never going to change. This portion of the driver is fixed.