Save information about the distribution in its dist_dir.

def save_info(self, dirn):
        '''
        Save information about the distribution in its dist_dir.
        '''
        with current_directory(dirn):
            info('Saving distribution info')
            with open('dist_info.json', 'w') as fileh:
                json.dump({'dist_name': self.ctx.dist_name,
                           'bootstrap': self.ctx.bootstrap.name,
                           'archs': [arch.arch for arch in self.ctx.archs],
                           'ndk_api': self.ctx.ndk_api,
                           'use_setup_py': self.ctx.use_setup_py,
                           'recipes': self.ctx.recipe_build_order + self.ctx.python_modules,
                           'hostpython': self.ctx.hostpython,
                           'python_version': self.ctx.python_recipe.major_minor_version_string},
                          fileh)