'Set up to cross-compile.
This is broken. We need to work out what the default
compile produces, and if not, THEN set the cross
compiler.'

def set_cross_cc(self, target_arch=None, cross_compile=None, build_target='bzImage'):

    if self.target_arch:
        return
    if (not self.build_target):
        self.set_build_target(build_target)
    if (target_arch is None):
        target_arch = utils.get_current_kernel_arch()
        if (target_arch == 'ppc64'):
            if (self.build_target == 'bzImage'):
                self.build_target = 'vmlinux'
    if (not cross_compile):
        cross_compile = self.job.config_get('kernel.cross_cc')
    if cross_compile:
        os.environ['CROSS_COMPILE'] = cross_compile
    elif ('CROSS_COMPILE' in os.environ):
        del os.environ['CROSS_COMPILE']
    return
    def install_package(package):
        raise NotImplementedError("I    don't    exist    yet!")
    if (target_arch in ['ppc64', 'ppc']):
        install_package('ppc64-cross')
        cross_compile = os.path.join(self.autodir, 'sources/ppc64-cross/bin')
    elif (target_arch == 'x86_64'):
        install_package('x86_64-cross')
        cross_compile = os.path.join(self.autodir, 'sources/x86_64-cross/bin')
    os.environ['ARCH'] = self.target_arch = target_arch
    self.cross_compile = cross_compile
    if self.cross_compile:
        os.environ['CROSS_COMPILE'] = self.cross_compile
