>>list of GCC is often borne out there, one has to grant that avr-gcc is
>>a dramatically superior product to any other offering for the target
>>CPU.

that's funny.  before i read it, i was just about to observe that our Atmel compiler
based on Plan 9's puts tables in program flash without any hints.
const alone wouldn't help anyway because the memory is accessed
using special instructions so the compiler and linker need to do
more analysis.  otherwise the compiler does reasonable well given
that the chip is really an 8-bit micro.  i think
the loader zl helps zc in some cases, and also monitors stack sizes.
it was important that the FFT and CC1000
tables go in program memory to save limited RAM,
although that feature was added fairly late.
we needed the atmel compiler for some work on motes.
i looked at gcc for it a bit initially whilst waiting for ours
but started to throw things or throw up; i can't remember which.