[PATCH 2/3] Look for include files in the directory of the including file.

[Jon Loeliger]

So, like, the other day David Gibson mumbled:
> > The doubly-linked list is intended to make it easier to construct search
> > path lists one-at-a-time from arguments in the proper order, without
> > needing to reverse the list at the end.
> 
> We've already got that problem with a bunch of the lists we create
> during parsing (we have several ugly add-to-end-of-singly-linked-list
> functions).  Going to doubly-linked lists might not be a bad idea, but
> we should do it across the board, probably using the kernel's list.h
> or something like it.

I would be happy to accept a kernel's-list.h-based refactoring
for doubly linked lists after the imminent 1.1 release!

jdl