Boxed NSObjects fail for Cocoapods installation

When installing the framework via Cocoapods, NSObject subclasses aren't properly boxed, due to the compiler conditional in Box.swift.

Here's a temporary workaround hook for a project's Podfile:

post_install do |installer|
    installer.pods_project.targets.each do |target|
        if target.name == "GRMustache.swift"
            target.build_configurations.each do |config|
                config.build_settings['OTHER_SWIFT_FLAGS'] ||= ['$(inherited)', '-DOBJC']
            end
        end
    end
end