Introduce `GenerateFreeStandingFunctionsClassName` option

src/Generator/Generators/CSharp/CSharpSources.cs

@@ -250,7 +250,8 @@ namespace CppSharp.Generators.CSharp
             if (!context.Functions.Any(f => f.IsGenerated) && !hasGlobalVariables)
                 return;
 
-            var parentName = SafeIdentifier(context.TranslationUnit.FileNameWithoutExtension);
+            var parentName = SafeIdentifier(Context.Options.GenerateFreeStandingFunctionsClassName?.Invoke(context.TranslationUnit)
+                                            ?? context.TranslationUnit.FileNameWithoutExtension);
             var isStruct = EnumerateClasses()
                 .ToList()
                 .FindAll(cls => cls.IsValueType && cls.Name == parentName && context.QualifiedLogicalName == cls.Namespace.QualifiedLogicalName)

src/Generator/Options.cs

@@ -172,6 +172,13 @@ namespace CppSharp
         public string IncludePrefix;
         public Func<TranslationUnit, string> GenerateName;
 
+        /// <summary>
+        /// By default the classes in which free standing functions are contained are named like the header they are in
+        /// this options allows you to customize this behavior.
+        /// </summary>
+        /// <remarks>C# only.</remarks>
+        public Func<TranslationUnit, string> GenerateFreeStandingFunctionsClassName;
+
         /// <summary>
         /// Set this option to the kind of comments that you want generated
         /// in the source code. This overrides the default kind set by the

tests/dotnet/CSharp/CSharp.Gen.cs

@@ -26,6 +26,8 @@ namespace CppSharp.Tests
 
             driver.ParserOptions.UnityBuild = true;
             driver.ParserOptions.AddSupportedFunctionTemplates("FunctionTemplate");
+
+            driver.Options.GenerateFreeStandingFunctionsClassName = t => t.FileNameWithoutExtension + "Cool";
         }
 
         public override void SetupPasses(Driver driver)