How to recompile with -Xlint:unchecked in Ant build task?

Add the following element in <javac></javac> section:

<compilerarg value="-Xlint:unchecked" />

In AndroidStudio, do this:

allprojects {
    tasks.withType(JavaCompile) {
        options.compilerArgs << "-Xlint:deprecation"
    }
}