// File: build.gradle
apply plugin: 'cpp'

class SpecialConfig {
    NativeComponentSpec componentSpec

    SpecialConfig(NativeComponentSpec componentSpec) {
        this.componentSpec = componentSpec
    }

    def something(boolean enabled) {
        componentSpec.sources {
            cpp {
                // Some important stuffs
            }
        }
    }
}

model {
    components {
        main(NativeLibrarySpec) {
            // How to bring this out ??
            project.extensions.create('specialConfig', SpecialConfig, it)

            // This is the new functionality I want to use
            specialConfig {
                something(true)
            }
        }
    }
}