[5.5] Extend the availability annotations for the Netrc support to cover all the Darwin platforms (#218)

This extends the availability based on the version numbers in the annotation for `NSTextCheckingResult.range(withName name: String) -> NSRange`.  Otherwise, ToolsSupportCore can no longer build on for example iOS, because the default minimum deployment targets for the various platforms are really old (e.g. iOS 9).

(cherry picked from commit d6c996e)

Author: abertelrud

Sources/TSCUtility/Netrc.swift

@@ -24,9 +24,9 @@ extension AuthorizationProviding {
 #if os(macOS)
 /*
  Netrc feature depends upon `NSTextCheckingResult.range(withName name: String) -> NSRange`,
- which is only available in macOS 10.13+ at this time.
+ which is only available in macOS 10.13+, iOS 11+, etc at this time.
  */
-@available (OSX 10.13, *)
+@available (macOS 10.13, iOS 11, tvOS 11, watchOS 4, *)
 /// Container of parsed netrc connection settings
 public struct Netrc: AuthorizationProviding {
     /// Representation of `machine` connection settings & `default` connection settings.
@@ -97,7 +97,7 @@ public struct Netrc: AuthorizationProviding {
     }
 }
 
-@available (OSX 10.13, *)
+@available (macOS 10.13, iOS 11, tvOS 11, watchOS 4, *)
 public extension Netrc {
     enum Error: Swift.Error {
         case invalidFilePath
@@ -135,14 +135,14 @@ public extension Netrc {
     }
 }
 
-@available (OSX 10.13, *)
+@available (macOS 10.13, iOS 11, tvOS 11, watchOS 4, *)
 extension Netrc.Error: CustomNSError {
     public var errorUserInfo: [String : Any] {
         return [NSLocalizedDescriptionKey: "\(self)"]
     }
 }
 
-@available (OSX 10.13, *)
+@available (macOS 10.13, iOS 11, tvOS 11, watchOS 4, *)
 fileprivate enum RegexUtil {
     @frozen fileprivate enum Token: String, CaseIterable {
         case machine, login, password, account, macdef, `default`