Diffing the results of conifgure

[Philip Prindeville]

 Hi.

We're passing a lot of information into configure manually because a lot of 
packages didn't used to handle cross-compilation correctly, but lately those 
packages have been getting better.

We'd like to start to peel away options that we pass to configure.

But, to ensure that the results are still correct, we'd want to capture the summary of results and diff files 
together, a "before" and "after" changes to our build infrastructure to make sure that 
the outputs are now discovered as the correct values, rather than being "forced" from the command 
line or environment.

confdefs.h is one idea, but I'm not sure it captures *all* of the state.  Does 
it?

config.log and config.status are too wordy, and their output can vary (based on 
autoconf versions) yet still come up with the correct final result, so those 
seem unlikely (unless we just extract the relevant portions of these).

What's the collective wisdom of the group?

Thanks,

-Philip