Change preprocessor macro LINUX to UNIX

src/Microsoft.PowerShell.PackageManagement/Cmdlets/CmdletBase.cs

@@ -477,7 +477,7 @@ namespace Microsoft.PowerShell.PackageManagement.Cmdlets {
         #region Event and telemetry stuff
         //Calling PowerShell Telemetry APIs
         protected void TraceMessage(string message, SoftwareIdentity swidObject) {
-#if !LINUX
+#if !UNIX
             TelemetryAPI.TraceMessage(message,
                 new {
                     PackageName = swidObject.Name,
@@ -510,7 +510,7 @@ namespace Microsoft.PowerShell.PackageManagement.Cmdlets {
 
         protected void LogEvent(EventTask task, EventId id, string context, string name, string version, string providerName, string source, string status, string destinationPath)
         {
-#if !LINUX
+#if !UNIX
             var iis = InitialSessionState.CreateDefault2();
 
             using (Runspace rs = RunspaceFactory.CreateRunspace(iis))

src/Microsoft.PowerShell.PackageManagement/project.json

@@ -10,7 +10,7 @@
 	"configurations": {
 		"Linux": {
 			"buildOptions": {
-				"define": ["LINUX"]
+				"define": ["UNIX"]
 			}
 		}
 	},