Enable MemberImportVisibility check - attempt 2

Enable MemberImportVisibility check on all targets. Use a standard
string header and footer to bracket the new block for ease of updating
in the future with scripts.

Package.swift

@@ -566,3 +566,14 @@ if Context.environment["SWIFTCI_USE_LOCAL_DEPS"] == nil {
         .package(path: "../swift-system"),
     ]
 }
+
+// ---    STANDARD CROSS-REPO SETTINGS DO NOT EDIT   --- //
+for target in package.targets {
+    if target.type != .plugin {
+        var settings = target.swiftSettings ?? []
+        // https://github.com/swiftlang/swift-evolution/blob/main/proposals/0444-member-import-visibility.md
+        settings.append(.enableUpcomingFeature("MemberImportVisibility"))
+        target.swiftSettings = settings
+    }
+}
+// --- END: STANDARD CROSS-REPO SETTINGS DO NOT EDIT --- //

Sources/NIOCrashTester/CrashTests+Strict.swift

@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 #if !canImport(Darwin) || os(macOS)
+import NIOCore
 import NIOPosix
 
 struct StrictCrashTests {

Sources/NIOCrashTester/CrashTests+System.swift

@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 #if !canImport(Darwin) || os(macOS)
+import NIOCore
 import NIOPosix
 import Foundation
 

Sources/NIOMulticastChat/main.swift

@@ -11,6 +11,7 @@
 // SPDX-License-Identifier: Apache-2.0
 //
 //===----------------------------------------------------------------------===//
+import CNIOLinux
 import NIOCore
 import NIOPosix
 

Sources/NIOPosix/BaseSocket.swift

@@ -12,6 +12,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+import CNIOLinux
 import NIOConcurrencyHelpers
 import NIOCore
 

Sources/NIOPosix/Bootstrap.swift

@@ -11,6 +11,7 @@
 // SPDX-License-Identifier: Apache-2.0
 //
 //===----------------------------------------------------------------------===//
+import CNIOLinux
 import NIOCore
 
 #if os(Windows)

Sources/NIOPosix/DatagramVectorReadManager.swift

@@ -11,6 +11,7 @@
 // SPDX-License-Identifier: Apache-2.0
 //
 //===----------------------------------------------------------------------===//
+import CNIOLinux
 import NIOCore
 
 /// An object that manages issuing vector reads for datagram channels.

Sources/NIOPosix/NonBlockingFileIO.swift

@@ -12,6 +12,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+import CNIOLinux
 import NIOConcurrencyHelpers
 import NIOCore
 

Sources/NIOPosix/PendingDatagramWritesManager.swift

@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 import Atomics
+import CNIOLinux
 import NIOCore
 
 private struct PendingDatagramWrite {

Sources/NIOPosix/PendingWritesManager.swift

@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 import Atomics
+import CNIOLinux
 import NIOCore
 
 private struct PendingStreamWrite {

Sources/NIOPosix/SelectorEpoll.swift

@@ -12,6 +12,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+import NIOConcurrencyHelpers
 import NIOCore
 
 #if !SWIFTNIO_USE_IO_URING

Sources/NIOPosix/Socket.swift

@@ -12,6 +12,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+import CNIOLinux
 import NIOCore
 
 /// The container used for writing multiple buffers via `writev`.

Sources/NIOPosix/SocketChannel.swift

@@ -11,6 +11,7 @@
 // SPDX-License-Identifier: Apache-2.0
 //
 //===----------------------------------------------------------------------===//
+import CNIOLinux
 import NIOCore
 
 #if os(Windows)