[tlbuild] Fail to set macros in c-auto.h for MinGW -- if not build in source tree

[Karl Berry]

    http://lists.gnu.org/archive/html/bug-autoconf/2010-09/msg00000.html

Thanks for the research.  From Eric (Blake)'s reply in that thread, I
see that patch was rejected for being unportable.  I don't think it
would be a good idea for us to override the autoconf developers in this
regard.

We're using the latest released autoconf, 2.69.  I would suggest raising
the issue with them if you wish.

As for other workarounds: Eric also suggests "using binary-mode mounts".
Maybe there is some way you can do something like that.  After all, if
something as fundamental as the /$/ regexp in awk has been broken, it's
likely to be a horrendous quagmire to step into.  (For one thing, I
would guess that the *.awk scripts I wrote for kpathsea itself won't
work either.)

Maybe others here have other ideas.

karl