Re-enable this bit of logic from before, which only sets a default opt_ah.h file if KERNBUILDDIR isn't defined.
Re-enable this bit of logic from before, which only sets a default
opt_ah.h file if KERNBUILDDIR isn't defined.

For now, AH_SUPPORT_AR5416 is required, so I'll just fix any
configuration file in /usr/src which is missing this option.

Pointy hat when things do break to:	adrian

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase