Use system included encodings.

.idea/.idea.Aaru/.idea/contentModel.xml

@@ -2051,6 +2051,7 @@
           <e p="LS120.cs" t="Include" />
           <e p="PocketZip.cs" t="Include" />
         </e>
+        <e p="Encoding.cs" t="Include" />
         <e p="Filesystems" t="Include">
           <e p="ADFS.cs" t="Include" />
           <e p="AFFS.cs" t="Include" />

Aaru.Gui/Aaru.Gui.csproj

@@ -23,6 +23,7 @@
     <PackageReference Include="Claunia.Encoding" Version="1.7.0" />
     <PackageReference Include="MessageBox.Avalonia" Version="0.9.6.1" />
     <PackageReference Include="OxyPlot.Avalonia-alpha-2020-04-15" Version="1.0.0" />
+    <PackageReference Include="System.Text.Encoding.CodePages" Version="4.7.1" />
     <PackageReference Include="Unclassified.NetRevisionTask" Version="0.3.0" />
     <PackageReference Include="Avalonia" Version="0.9.10" />
     <PackageReference Include="Avalonia.Desktop" Version="0.9.10" />

Aaru.Gui/Main.cs

@@ -1,3 +1,4 @@
+using System.Text;
 using Avalonia;
 using Avalonia.Dialogs;
 using Avalonia.Logging.Serilog;
@@ -7,7 +8,12 @@ namespace Aaru.Gui
 {
     public static class Main
     {
-        public static int Start(string[] args) => BuildAvaloniaApp().StartWithClassicDesktopLifetime(args);
+        public static int Start(string[] args)
+        {
+            Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
+
+            return BuildAvaloniaApp().StartWithClassicDesktopLifetime(args);
+        }
 
         // Avalonia configuration, don't remove; also used by visual designer.
         public static AppBuilder BuildAvaloniaApp() => AppBuilder.

Aaru.Tests/Aaru.Tests.csproj

@@ -7,9 +7,11 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="Claunia.Encoding" Version="1.7.0" />
     <PackageReference Include="nunit" Version="3.12.0" />
     <PackageReference Include="NUnit3TestAdapter" Version="3.15.1" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.4.0" />
+    <PackageReference Include="System.Text.Encoding.CodePages" Version="4.7.1" />
   </ItemGroup>
 
   <ItemGroup>

Aaru.Tests/Encoding.cs

@@ -0,0 +1,12 @@
+using System.Text;
+using NUnit.Framework;
+
+namespace Aaru.Tests
+{
+    [SetUpFixture]
+    public class Encoding
+    {
+        [OneTimeSetUp]
+        public void EnableEncodings() => System.Text.Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
+    }
+}