can automatically use the AH_XXX options that the HAL was built, without
requiring additional machine-specific configuration.
A follow up commit will activate this change.
the rules due to needing to conditionally postprocess the HAL object file.
Macppc needs a a non-ELF HAL (EABI) object, so take care of that by default
in the atheros include file.
including easy override mechanism for ports that need it.
To use this, just .include this file instead of listing explicit rules
for building the target. A change to std/conf/files will be made shortly
that lists /athhal.o as an object if "ath" is defined.
If you need to override the default HAL selected for some reason (for example
to use an xscale version of the HAL on evbarm kernels that support it), add
a "makeoptions ATH_MACHINE_HAL=<hal>", for example to select the XScale
LE configuration you could use "makeoptions ATH_MACHINE_HAL=xscale-le-elf".
