module os_availability [system] {
  // General purpose API.
  header "os/availability.h"
  export *

  // Alternative API where os/availability.h can't
  // be used, such as in POSIX headers.
  explicit module Availability {
    header "Availability.h"
    export *
  }
}

// Implementation details, use os_availability.
module os_availability_internal [system] {
  explicit module AvailabilityInternal {
    header "AvailabilityInternal.h"
    export *
  }

  explicit module AvailabilityInternalLegacy {
    header "AvailabilityInternalLegacy.h"
    export *
  }

  explicit module AvailabilityVersions {
    header "AvailabilityVersions.h"
    export *
  }
}

// Deprecated, use Availability.
module AvailabilityMacros [system] {
  header "AvailabilityMacros.h"
  export *
}