chainport: the midipix porting bits for everything but the compiler

the chainport repository contains the patches required for building
a midipix-targeting toolchain; at the moment, this primarily means
patches for binutils and the gcc dependency libraries, as well as
libffi and python.

porting applications and libraries to midipix can often be done with
no changes to the code proper. at the time of this writing, midipix
target information has already been added to upstream config.sub,
however since some package are slow to update it, you may want to
unconditionally replace a package's config.sub with the cached copy
of config.sub that is included with this repository.

for the sake of convenience and simplicity, the patch for each supported
version of an upstream source tree is named package-x.y.z.midipix.patch.

for packages not using libtool, building for a midipix target should
only require the above patch file. packages which do depend on libtool
can be easily built with slibtool (dl.midipix.org/slibtool) in the
following way:

$ export MAKE="make LIBTOOL=slibtool"
$ ./configure --host=... && make && make install

a few packages (most notably binutils and gdb) require that you replace
'slibtool' with 'slibtool-static' in the above export statement.