Patches were submitted upstream and the answer was:

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Yes, I assume host == build  in all releases to date.  AFAIK you are the
first to try a canadian-cross build.

Another issue  is that the build is not set up to do the build anywhere
but inside the source tree.  It is true that make-clean/CLEANUP fixes up
the mess pretty well, but a separate build directory would be a nice
(and traditional) thing to allow.

I cannot use your submission for anything (Linaro and I have no
agreement in place) but  I think these are interesting and worthwhile
small issues that libdwarf/dwarfdump should be able to deal with.

Thanks for the suggestion.  I made a note and should be able to take a
look at this issue in the near future. 
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