a more elegant way to build products conditionally

Product {
    // dependencies being unsatisfied breaks the build by default, ...
    importance: Recommended
    // ... but the product can be manually excluded
    //enabled: true // that's actually the default

    Depends {
        name: "OpenSSL"
        // absence prevents build
        importance: Mandatory
    }
    Depends {
        name: "Botan"
        // absence does not prevent build 
        importance: Suggested
    }
}

Product {
    // dependencies being unsatisfied excludes it from the build
    importance: Suggested

    Depends {
        name: "OpenSSL"
        // absence breaks build by default, but can be disabled
        importance: Recommended
    }
}