Disable D2D1 generator if unsafe blocks are not allowed

src/ComputeSharp.D2D1.SourceGenerators/ID2D1ShaderGenerator.cs

@@ -36,6 +36,12 @@ public void Initialize(IncrementalGeneratorInitializationContext context)
                 static (node, _) => node.IsTypeDeclarationWithOrPotentiallyWithBaseTypes<StructDeclarationSyntax>(),
                 static (context, token) =>
                 {
+                    // The source generator requires unsafe blocks to be enabled (eg. for pointers, [SkipLocalsInit], etc.)
+                    if (!context.SemanticModel.Compilation.IsAllowUnsafeBlocksEnabled())
+                    {
+                        return default;
+                    }
+
                     StructDeclarationSyntax typeDeclaration = (StructDeclarationSyntax)context.Node;
 
                     // If the type symbol doesn't have at least one interface, it can't possibly be a shader type

src/ComputeSharp.SourceGeneration/Extensions/CompilationExtensions.cs

@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
 
 namespace ComputeSharp.SourceGeneration.Extensions;
 
@@ -11,6 +12,16 @@ namespace ComputeSharp.SourceGeneration.Extensions;
 /// </summary>
 internal static class CompilationExtensions
 {
+    /// <summary>
+    /// Checks whether the <c>AllowUnsafeBlocks</c> option is set for a given compilation.
+    /// </summary>
+    /// <param name="compilation">The <see cref="Compilation"/> object to check.</param>
+    /// <returns>Whether the <c>AllowUnsafeBlocks</c> option is set for <paramref name="compilation"/>.</returns>
+    public static bool IsAllowUnsafeBlocksEnabled(this Compilation compilation)
+    {
+        return compilation.Options is CSharpCompilationOptions { AllowUnsafe: true };
+    }
+
     /// <summary>
     /// <para>
     /// Checks whether or not a type with a specified metadata name is accessible from a given <see cref="Compilation"/> instance.