Example

<property name="repo.dir" value="./relative/path/to/repo" />
<resolvepath propertyName="repo.dir.resolved" file="${repo.dir}" />

<!-- Clone repository -->
<gitclone 
    repository="git://github.com/path/to/repo/repo.git"
    targetPath="${repo.dir.resolved}" />

<!-- Cleanup repository-->
<gitgc 
    repository="${repo.dir.resolved}" 
    aggressive="true"
    prune="1.week.ago" />