patch older config.guess for newer architectures (#2221)

lib/spack/docs/packaging_guide.rst

lib/spack/spack/build_systems/autotools.py

var/spack/repos/builtin/packages/cairo/package.py

var/spack/repos/builtin/packages/dyninst/package.py

var/spack/repos/builtin/packages/fontconfig/package.py

var/spack/repos/builtin/packages/graphviz/package.py

var/spack/repos/builtin/packages/libelf/package.py

var/spack/repos/builtin/packages/libiconv/package.py

var/spack/repos/builtin/packages/libtiff/package.py

var/spack/repos/builtin/packages/lzma/package.py

var/spack/repos/builtin/packages/py-pygobject/package.py

var/spack/repos/builtin/packages/py-pygtk/package.py