yes, in the build process auto.inc is only depending on auto.c but in the real world this is not true. To fix this we would probably need to create dependencies with gcc -MM (can we use gcc, or would romcc have to do this? Eric?) I did this dynamically for the flashrom utility a while ago, but for all of LinuxBIOS this would be a major task.
Currently I'm just 'rm'ing auto.inc and auto.c (auto.* actually) in the target as part of my build process. Perhaps thats a good short term fix? Re-generate auto.c every time?
One thing that desperately needs to happen is to pack all the preprocessor macros into a .h file and include it, be it by replacing all of them with a single --include preproc.h.
I've done a bit of work on this. I've tweaked the generated config.py so that outputs all the variables into a file called _board_options.h as #define VAR VALUE.
The problem is that some of those variable strings need to be interperted by the shell to get the right values. And several of them will not pass the compiler as is.
Currently I don't see any method of figureing out what variables are ok for adding to the _board_options.h file.
I was thinking of extending the options.lb file to include a "scope" parameter that indicates if the variable is ok for inclusion in to the _board_options.h file or if it needs to go to the shell and make system.
Any other ideas or perhaps something simpler?