This can be accomplished in one of two ways:

1) Pull the file from your device:
cd /your/repo/path
adb pull /system/etc/build-manifest.xml .repo/manifests/cm-10.0.0.xml

OR

2) Extract /system/etc/build-manifest.xml from the ROM zip and place it manually.

等于这样你就有了这个版本CM build的manifests.xml。

Enabling the Manifest

Switch to this new manifest and enable it by typing:
repo init -m cm-10.0.0.xml 
repo sync

To go back to mainline:
repo init -m default.xml 
repo sync

-m就是使用本地文件，-u就是使用URL了。