Add special marshaling attribute to delegate declaration if calling convention differs.

src/Generator/Generators/CLI/CLIHeadersTemplate.cs

@@ -714,7 +714,31 @@ namespace CppSharp.Generators.CLI
                 PushBlock(CLIBlockKind.Typedef, typedef);
                 GenerateDeclarationCommon(typedef);
 
-                var insideClass = typedef.Namespace is Class;
+                var insideClass = typedef.Namespace is Class;
+
+                string callingConvention = null;
+                switch (function.CallingConvention)
+                {
+                    case CallingConvention.C:
+                        callingConvention = "Cdecl";
+                        break;
+                    case CallingConvention.StdCall:
+                        callingConvention = "StdCall";
+                        break;
+                    case CallingConvention.ThisCall:
+                        callingConvention = "ThisCall";
+                        break;
+                    case CallingConvention.FastCall:
+                        callingConvention = "FastCall";
+                        break;
+                }
+                if (callingConvention != null)
+                {
+                    WriteLine("[{0}({1}::{2})] ",
+                        "System::Runtime::InteropServices::UnmanagedFunctionPointer",
+                        "System::Runtime::InteropServices::CallingConvention",
+                        callingConvention);
+                }
 
                 WriteLine("{0}{1};",
                     !insideClass ? "public " : "",