The whole #ifdef vs. #if is a very old argument in linuxbios/coreboot.
initially, it was #ifdef in old v1. Then, later, there was a feeling it should be linux style, #if.
The change from #ifdef to #if caused lots of silent failures. Now we're changing back.
The main thing is that we have to be consistent. I am not particular either way, but it is important to understand that this argument has been ongoing, with strong discussion over the years.
ron