生成 CIPD 文件以下载当前的 QEMU 软件包。
Usage: fx qemu-cipd-ensure
This looks at the current jiri checkout to find the QEMU package version
to use. Then it generates CIPD files that you can copy over to any
machine and use to get the QEMU package installed locally there. This
works even if build host where you run this script and the place you use
the output are different OS or machine types.
The files `qemu-cipd.ensure` and `qemu-cipd.versions` will be generated
in the current build directory. Comments in `qemu-cipd.ensure` explain
how to use these files. It should work on any machine connected to the
Internet with no prior setup.