Do the targetarch dependency stuff better.

Do the targetarch dependency stuff better.

SConscript:
    targetarch is only for headers, not cc files.  move all cc files
    back to arch/alpha, and make the target arch directory do this
    echo '#include "arch/alpha/foo.hh"' > targetarch/foo.hh for every
    header file.  This works a lot better and doesn't kill emacs'
    ability to parse compile outputs

--HG--
extra : convert_revision : c1d51643bdc457ae2d96c5f50d3ef1c6a58a600d