[Darwin] Import all overlay shims with @_implementationOnly

Author: lorentey

stdlib/public/Darwin/Dispatch/Block.swift

@@ -10,7 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-import _SwiftDispatchOverlayShims
+@_implementationOnly import _SwiftDispatchOverlayShims
 
 public struct DispatchWorkItemFlags : OptionSet, RawRepresentable {
 	public let rawValue: UInt

stdlib/public/Darwin/Dispatch/Data.swift

@@ -10,7 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-import _SwiftDispatchOverlayShims
+@_implementationOnly import _SwiftDispatchOverlayShims
 
 public struct DispatchData : RandomAccessCollection, _ObjectiveCBridgeable {
 	public typealias Iterator = DispatchDataIterator

stdlib/public/Darwin/Dispatch/Dispatch.swift

@@ -11,7 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 @_exported import Dispatch
-import _SwiftDispatchOverlayShims
+@_implementationOnly import _SwiftDispatchOverlayShims
 
 /// dispatch_assert
 

stdlib/public/Darwin/Dispatch/Queue.swift

@@ -12,7 +12,7 @@
 
 // dispatch/queue.h
 
-import _SwiftDispatchOverlayShims
+@_implementationOnly import _SwiftDispatchOverlayShims
 
 public final class DispatchSpecificKey<T> {
 	public init() {}

stdlib/public/Darwin/Dispatch/Source.swift

@@ -11,7 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 // import Foundation
-import _SwiftDispatchOverlayShims
+@_implementationOnly import _SwiftDispatchOverlayShims
 
 extension DispatchSourceProtocol {
 	public typealias DispatchSourceHandler = @convention(block) () -> Void

stdlib/public/Darwin/Dispatch/Time.swift

@@ -11,7 +11,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-import _SwiftDispatchOverlayShims
+@_implementationOnly import _SwiftDispatchOverlayShims
 
 public struct DispatchTime : Comparable {
 	private static let timebaseInfo: mach_timebase_info_data_t = {

stdlib/public/Darwin/Network/NWConnection.swift

@@ -12,7 +12,7 @@
 
 import Dispatch
 import Foundation
-import _SwiftNetworkOverlayShims
+@_implementationOnly import _SwiftNetworkOverlayShims
 
 /// An NWConnection is an object that represents a bi-directional data pipe between
 /// a local endpoint and a remote endpoint.

stdlib/public/Darwin/Network/NWEndpoint.swift

@@ -12,7 +12,7 @@
 
 import Darwin
 import Foundation
-import _SwiftNetworkOverlayShims
+@_implementationOnly import _SwiftNetworkOverlayShims
 
 internal extension sockaddr_in {
 	init(_ address:in_addr, _ port: in_port_t) {

stdlib/public/Darwin/Network/NWError.swift

@@ -12,7 +12,7 @@
 
 import Darwin
 import Security
-import _SwiftNetworkOverlayShims
+@_implementationOnly import _SwiftNetworkOverlayShims
 
 /// NWError is a type to deliver error codes relevant to NWConnection and NWListener objects.
 /// Generic connectivity errors will be delivered in the posix domain, resolution errors will

stdlib/public/Darwin/Network/NWPath.swift

@@ -11,7 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 import Foundation
-import _SwiftNetworkOverlayShims
+@_implementationOnly import _SwiftNetworkOverlayShims
 
 /// An NWInterface object represents an instance of a network interface of a specific
 /// type, such as a Wi-Fi or Cellular interface.