Gradle ant subproject dependency ordering - ant

Question

I've got a project with 6 subprojects that have ant build.xml files in them. I'm trying to write a top level gradle file that will do the ant 'default' task on all the projects, respecting their order dependencies. So I have this in settings.gradle (which happens to be the order I want them run in):
include 'core', 'api-web', 'execution', 'cluster', 'persistence', 'choreo-tests'
And I have this in my top level build.gradle:
project(':api-web') {
dependencies {
compile project(':core')
}
}
project(':execution') {
dependencies {
compile project(':api-web')
}
}
project(':cluster') {
dependencies {
compile project(':execution')
}
}
project(':persistence') {
dependencies {
compile project(':cluster')
}
}
project(':choreo-tests') {
dependencies {
compile project(':persistence')
}
}
And then each directory has this in its build.gradle:
ant.importBuild 'build.xml'
However, if I try to run this:
gradle --info default
I get this output:
> Could not find method compile() for arguments [project ':core'] on org.gradle.api.internal.artifacts.dsl.dependencies.DefaultDependencyHandler_Decorated#4d12bc7b.
I don't understand, since the build.xml files all have a compile target. Is there something I need to do to have the ant build.xml files get loaded into their own namespace?
Or, more specifically, after having loaded these subprojects, which contain gradle tasks created from the ant targets, how can I specify the dependencies between subprojects tasks? Every build.xml I have has a 'default' task. How do I specify that my 'default' task in project(':api-web') depends on the 'default' task of project(':core')?