[Patch] Fixup more relative directories when building --enable-debug

[Benjamin Kosnik]

>I'm finally getting a chance to try out the new --enable-debug, and I
>ran into a snag when compiling off the cvs trunk.  Some of the errors
>are shown below.

Huh. How are you configuring? Are you using separate build and src
directories? (Just curious)

>I think that src/Makefile.in just needs a few more directories fixed.
>I've guessed at which ones need manipulated based on which ones
>started with "../" in my build directory's debug/Makefile.  A patch
>that made it build (and install) cleanly from scratch is attached.

Hmm. Ok: these looks like acceptable fixups to me. I'm toying with
putting this patch, plus the fixups from Phil and others onto
3_3-branch. 

> And by the way, is there a reason this isn't just done with a pipe? 

No. I didn't know how else to do it, and the other ways I could think of
ended up not working. As it stands, the additional debug rule is pretty
small, so if you can think of a better way to do this feel free.

-benjamin