RxTests compiles first time on Linux.

RxTests/Event+Equatable.swift

@@ -19,18 +19,24 @@ public func == <Element: Equatable>(lhs: Event<Element>, rhs: Event<Element>) ->
     switch (lhs, rhs) {
     case (.Completed, .Completed): return true
     case (.Error(let e1), .Error(let e2)):
-        let error1 = e1 as NSError
-        let error2 = e2 as NSError
-
         // if the references are equal, then it's the same object
-        if let lhsObject = lhs as? AnyObject, rhsObject = rhs as? AnyObject where lhsObject === rhsObject {
+        if let  lhsObject = lhs as? AnyObject,
+                rhsObject = rhs as? AnyObject
+                where lhsObject === rhsObject {
             return true
         }
-        
-        return error1.domain == error2.domain
-            && error1.code == error2.code
-            && "\(e1)" == "\(e2)"
+
+        #if os(Linux)
+          return  "\(e1)" == "\(e2)"
+        #else
+          let error1 = e1 as NSError
+          let error2 = e2 as NSError
+
+          return error1.domain == error2.domain
+              && error1.code == error2.code
+              && "\(e1)" == "\(e2)"
+        #endif
     case (.Next(let v1), .Next(let v2)): return v1 == v2
     default: return false
     }
-}
+}