Add ILibrary.GenerateCode as a custom code generation callback.

src/CLI/Generator.cs

@@ -174,6 +174,10 @@ namespace CppSharp
             driver.Context.TranslationUnitPasses.AddPass(new MarshalPrimitivePointersAsRefTypePass());
         }
 
+        public void GenerateCode(Driver driver, List<GeneratorOutput> outputs)
+        {
+        }
+
         public void Preprocess(Driver driver, ASTContext ctx)
         {
         }

src/Generator/Driver.cs

@@ -486,6 +486,8 @@ namespace CppSharp
                 {
                     var outputs = driver.GenerateCode();
 
+                    library.GenerateCode(driver, outputs);
+
                     foreach (var output in outputs)
                     {
                         foreach (var pass in driver.Context.GeneratorOutputPasses.Passes)

src/Generator/Library.cs

@@ -4,6 +4,7 @@ using System.Globalization;
 using System.Linq;
 using System.Text.RegularExpressions;
 using CppSharp.AST;
+using CppSharp.Generators;
 using CppSharp.Passes;
 
 namespace CppSharp
@@ -33,6 +34,11 @@ namespace CppSharp
         /// </summary>
         /// <param name="driver"></param>
         void SetupPasses(Driver driver);
+
+        /// <summary>
+        /// Generate custom code here.
+        /// </summary>
+        void GenerateCode(Driver driver, List<GeneratorOutput> outputs) { }
     }
 
     public static class LibraryHelpers