update osx detection

Emby.Common.Implementations/EnvironmentInfo/EnvironmentInfo.cs

@@ -10,11 +10,17 @@ namespace Emby.Common.Implementations.EnvironmentInfo
     public class EnvironmentInfo : IEnvironmentInfo
     {
         public MediaBrowser.Model.System.Architecture? CustomArchitecture { get; set; }
+        public MediaBrowser.Model.System.OperatingSystem? CustomOperatingSystem { get; set; }
 
         public MediaBrowser.Model.System.OperatingSystem OperatingSystem
         {
             get
             {
+                if (CustomOperatingSystem.HasValue)
+                {
+                    return CustomOperatingSystem.Value;
+                }
+
 #if NET46
                 switch (Environment.OSVersion.Platform)
                 {

MediaBrowser.Server.Mac/Main.cs

@@ -142,7 +142,10 @@ namespace MediaBrowser.Server.Mac
 
         private static EnvironmentInfo GetEnvironmentInfo()
         {
-            var info = new EnvironmentInfo();
+            var info = new EnvironmentInfo()
+            {
+                CustomOperatingSystem = MediaBrowser.Model.System.OperatingSystem.OSX
+            };
 
             var uname = GetUnixName();