LOL *rolls on floor laughing*. That's a good one! You do realise that we're talking about kernels here, right? Compilers don't know about page tables, or context switching, or power management, or interrupts (on most platforms), or any of a number of important architecture-specific things that kernels need to manage. The code to handle this is in the architecture-dependant arch/ directories of the Linux kernel. (I believe the BSDs handle the seperation between architecture-independant and architecture-specific code differently. Never used them though.)

Android is not Linux. Developing Android drivers and porting it to a new hardware platform is not that similar to developing Linux drivers and porting that to a new platform. Android's based on the Linux kernel, but it has enough fundamental changes to the driver APIs that they're not really compatible.