Make sure that Krb5ConfigDefaults uses correct values on each supported platform

use .NET 8 updated OS detection
but change as little code as possible

Author: petrsnd

Kerberos.NET/Configuration/Krb5ConfigDefaults.cs

@@ -53,8 +53,10 @@ public class Krb5ConfigDefaults : Krb5ConfigObject
         [DefaultValue("FILE:%APPDATA%\\Kerberos.NET\\.krb5cc")]
 #elif LINUX
         [DefaultValue("FILE:%HOME%/.config/Kerberos.NET/.krb5cc")]
-#else
+#elif MACOS
         [DefaultValue("FILE:%HOME%/Library/Preferences/Kerberos.NET/.krb5cc")]
+#else
+        #error Unknown platform
 #endif
         [DisplayName("default_ccache_name")]
         public string DefaultCCacheName { get; set; }
@@ -66,8 +68,10 @@ public class Krb5ConfigDefaults : Krb5ConfigObject
         [DefaultValue("%APPDATA%\\Kerberos.NET\\client.keytab")]
 #elif LINUX
         [DefaultValue("%HOME%/.config/Kerberos.NET/client.keytab")]
-#else
+#elif MACOS
         [DefaultValue("%HOME%/Library/Preferences/Kerberos.NET/client.keytab")]
+#else
+        #error Unknown platform
 #endif
         [DisplayName("default_client_keytab_name")]
         public string DefaultClientKeytabName { get; set; }
@@ -79,8 +83,10 @@ public class Krb5ConfigDefaults : Krb5ConfigObject
         [DefaultValue("%APPDATA%\\Kerberos.NET\\server.keytab")]
 #elif LINUX
         [DefaultValue("%HOME%/.config/Kerberos.NET/server.keytab")]
-#else
+#elif MACOS
         [DefaultValue("%HOME%/Library/Preferences/Kerberos.NET/server.keytab")]
+#else
+        #error Unknown platform
 #endif
         [DisplayName("default_keytab_name")]
         public string DefaultKeytabName { get; set; }

Kerberos.NET/Kerberos.NET.csproj

@@ -13,6 +13,18 @@
     <DefineConstants>WEAKCRYPTO</DefineConstants>
   </PropertyGroup>
 
+  <PropertyGroup Condition=" '$(OS)' == 'Windows_NT' ">
+    <DefineConstants>$(DefineConstants);WINDOWS</DefineConstants>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(OS)' == 'Unix' And $(NETCoreSdkPortableRuntimeIdentifier.StartsWith('linux'))">
+    <DefineConstants>$(DefineConstants);LINUX</DefineConstants>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(OS)' == 'Unix' And $(NETCoreSdkPortableRuntimeIdentifier.StartsWith('osx'))">
+    <DefineConstants>$(DefineConstants);MACOS</DefineConstants>
+  </PropertyGroup>
+
   <ItemGroup>
     <AdditionalFiles Include="..\stylecop.json" Link="stylecop.json" />
   </ItemGroup>

Kerberos.NET/OSPlatform.cs

@@ -1,16 +1,14 @@
 using System;
+using RtIs = System.Runtime.InteropServices;
 
 namespace Kerberos.NET
 {
     public static class OSPlatform
     {
-        public static readonly bool IsWindows = Environment.OSVersion.Platform == PlatformID.Win32S
-                                             || Environment.OSVersion.Platform == PlatformID.Win32Windows
-                                             || Environment.OSVersion.Platform == PlatformID.Win32NT
-                                             || Environment.OSVersion.Platform == PlatformID.WinCE;
+        public static readonly bool IsWindows = RtIs.RuntimeInformation.IsOSPlatform(RtIs.OSPlatform.Windows);
 
-        public static readonly bool IsLinux = Environment.OSVersion.Platform == PlatformID.Unix;
+        public static readonly bool IsLinux = RtIs.RuntimeInformation.IsOSPlatform(RtIs.OSPlatform.Linux);
 
-        public static readonly bool IsOsX = Environment.OSVersion.Platform == PlatformID.MacOSX;
+        public static readonly bool IsOsX = RtIs.RuntimeInformation.IsOSPlatform(RtIs.OSPlatform.OSX);
     }
 }