Hide obsolete platform IDs from Editor

Author: ViktorHofer

src/System.Runtime.Extensions/ref/System.Runtime.Extensions.cs

@@ -857,13 +857,13 @@ public void GetObjectData(System.Runtime.Serialization.SerializationInfo info, S
     }
     public enum PlatformID
     {
-        Win32S = 0,
-        Win32Windows = 1,
+        [ComponentModel.EditorBrowsable(ComponentModel.EditorBrowsableState.Never)] Win32S = 0,
+        [ComponentModel.EditorBrowsable(ComponentModel.EditorBrowsableState.Never)] Win32Windows = 1,
         Win32NT = 2,
-        WinCE = 3,
+        [ComponentModel.EditorBrowsable(ComponentModel.EditorBrowsableState.Never)] WinCE = 3,
         Unix = 4,
-        Xbox = 5,
-        MacOSX = 6
+        [ComponentModel.EditorBrowsable(ComponentModel.EditorBrowsableState.Never)] Xbox = 5,
+        [ComponentModel.EditorBrowsable(ComponentModel.EditorBrowsableState.Never)] MacOSX = 6
     }
     public partial class Progress<T> : System.IProgress<T>
     {

src/System.Runtime.Extensions/src/System/Environment.Unix.cs

@@ -327,6 +327,8 @@ public static string MachineName
                 revision = FindAndParseNextNumber(release, ref i);
             }
 
+            // For compatibility reasons with Mono, PlatformID.Unix is returned on MacOSX. PlatformID.MacOSX
+            // is hidden from the editor and shouldn't be used.
             return new OperatingSystem(PlatformID.Unix, new Version(major, minor, build, revision));
         });
 

src/System.Runtime.Extensions/src/System/PlatformID.cs

@@ -2,16 +2,18 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System.ComponentModel;
+
 namespace System
 {
     public enum PlatformID
     {
-        Win32S = 0,
-        Win32Windows = 1,
+        [EditorBrowsable(EditorBrowsableState.Never)] Win32S = 0,
+        [EditorBrowsable(EditorBrowsableState.Never)] Win32Windows = 1,
         Win32NT = 2,
-        WinCE = 3,
+        [EditorBrowsable(EditorBrowsableState.Never)] WinCE = 3,
         Unix = 4,
-        Xbox = 5,
-        MacOSX = 6
+        [EditorBrowsable(EditorBrowsableState.Never)] Xbox = 5,
+        [EditorBrowsable(EditorBrowsableState.Never)] MacOSX = 6
     }
 }