I agree.
> either I have to add tons of #if this_kernel_vesion etc. or I have to
> change [many?] application sources if the kernel header files change
> (e.g. one more entry in a structure...)
They are not talking about application sources, but the libc stuff.
They want to allow people to compile stuff without installing the
kernel.
I think that using the kernel includes for applications is a good
thing. This way, you are guaranteed consistency between applications
and the kernel. Yes, the kernel developers know that changing a header
file that applications use too, would require the applications to be
recompiled. So these changes are not applied to lightly.
If you have a separate include file, that would also have to be made
in-sync with the kernel to be able to compile the application. More
work. And harder to find!
Roger.