Fix Swift 4.2 compatibility on Linux

Author: ikesyo

Sources/Nimble/Matchers/BeIdenticalTo.swift

@@ -4,14 +4,14 @@ import Foundation
 /// as the expected instance.
 public func beIdenticalTo(_ expected: Any?) -> Predicate<Any> {
     return Predicate.define { actualExpression in
-        #if os(Linux)
+        #if os(Linux) && !swift(>=4.1.50)
             let actual = try actualExpression.evaluate() as? AnyObject
         #else
             let actual = try actualExpression.evaluate() as AnyObject?
         #endif
 
         let bool: Bool
-        #if os(Linux)
+        #if os(Linux) && !swift(>=4.1.50)
             bool = actual === (expected as? AnyObject) && actual !== nil
         #else
             bool = actual === (expected as AnyObject?) && actual !== nil

Sources/Nimble/Utils/Await.swift

@@ -261,7 +261,7 @@ internal class AwaitPromiseBuilder<T> {
             self.trigger.timeoutSource.resume()
             while self.promise.asyncResult.isIncomplete() {
                 // Stopping the run loop does not work unless we run only 1 mode
-                #if swift(>=4.2)
+                #if swift(>=4.2) && (os(macOS) || os(iOS) || os(tvOS))
                 _ = RunLoop.current.run(mode: .default, before: .distantFuture)
                 #else
                 _ = RunLoop.current.run(mode: .defaultRunLoopMode, before: .distantFuture)

Sources/Nimble/Utils/Stringers.swift

@@ -2,7 +2,7 @@ import Foundation
 
 internal func identityAsString(_ value: Any?) -> String {
     let anyObject: AnyObject?
-#if os(Linux)
+#if os(Linux) && !swift(>=4.1.50)
     anyObject = value as? AnyObject
 #else
     anyObject = value as AnyObject?

test

@@ -84,7 +84,7 @@ function test_podspec {
 
 function test_swiftpm {
     if [ -d .build ]; then
-        run swift build --clean
+        run swift package clean
     fi
     run swift build && swift test
 }