except BaseException as err:
        output = b''

    if bytes(args.o.ver, 'utf-8') in output:
        print('{app} {ver} is already installed'.format(app=args.o.src, ver=VER))
        exit(0)
    else:
        print('compiling {app} {ver}'.format(app=args.o.src, ver=VER))
        os.makedirs(args.o.src, exist_ok=True)

        try:
            url = 'git://git.qemu.org/qemu.git'
            utils.git('clone', [url, args.o.src])
            os.chdir(args.o.src)
            utils.git('checkout', ['v{ver}'.format(ver=VER)])
            utils.git('submodule', ['update', '--init', 'dtc'])
            os.mkdir('build')
            os.chdir('build')
        except BaseException as ex:
            traceback.print_exc()
            exit(1)

        print('configure')
        utils.bashPython2(
                '../configure --prefix={} --target-list=arm-softmmu,arm-linux-user'
                .format(args.o.prefix))
        utils.bashPython2('make -j {}'.format(multiprocessing.cpu_count()))
        utils.bashPython2('make install')

        exit(0)