C#, D, Java methodmodifiers on destructors

Add support so that the %csmethodmodifiers, %dmethodmodifiers,
%javamethodmodifiers can modify the method modifiers for the destructor wrappers
in the proxy class: dispose, Dispose, delete. With this feature, it is now possible
to make a C# proxy class sealed, eg when wrapping a class X, the virtual method modifiers
can be removed using:

  %typemap(csclassmodifiers) X "public sealed class"
  %csmethodmodifiers X::~X "public /*virtual*/";

Examples/test-suite/common.mk

@@ -170,6 +170,7 @@ CPP_TEST_CASES += \
 	defvalue_constructor \
 	derived_byvalue \
 	derived_nested \
+	destructor_methodmodifiers \
 	destructor_reprotected \
 	director_abstract \
 	director_alternating \

Examples/test-suite/destructor_methodmodifiers.i

@@ -0,0 +1,61 @@
+%module destructor_methodmodifiers
+
+// This test changes the proxy classes so that they cannot be inherited from in the target language
+// Previously the %csmethodmodifiers, %dmethodmodifiers, %javamethodmodifiers on destructors were ignored
+// Now they can control the dispose/Dispose/delete method modifiers
+
+#if defined(SWIGCSHARP)
+
+// remove all use of protected and virtual keywords
+%typemap(csclassmodifiers) NotForDeriving1, NotForDeriving2 "public sealed class"
+%csmethodmodifiers NotForDeriving1::~NotForDeriving1 "public /*not virtual nor override*/";
+%csmethodmodifiers NotForDeriving2::~NotForDeriving2 "public /*not virtual nor override*/";
+
+// remove protected keyword to remove compiler warning
+%typemap(csbody) NotForDeriving1, NotForDeriving2 %{
+  private global::System.Runtime.InteropServices.HandleRef swigCPtr;
+  private /*protected*/ bool swigCMemOwn;
+
+  internal $csclassname(global::System.IntPtr cPtr, bool cMemoryOwn) {
+    swigCMemOwn = cMemoryOwn;
+    swigCPtr = new global::System.Runtime.InteropServices.HandleRef(this, cPtr);
+  }
+
+  internal static global::System.Runtime.InteropServices.HandleRef getCPtr($csclassname obj) {
+    return (obj == null) ? new global::System.Runtime.InteropServices.HandleRef(null, global::System.IntPtr.Zero) : obj.swigCPtr;
+  }
+%}
+
+#elif defined(SWIGD)
+
+%typemap(dclassmodifiers) NotForDeriving1, NotForDeriving2 "final class"
+%dmethodmodifiers NotForDeriving1::~NotForDeriving1 "public final";
+%dmethodmodifiers NotForDeriving2::~NotForDeriving2 "public final";
+
+#elif defined(SWIGJAVA)
+
+%typemap(javaclassmodifiers) NotForDeriving1, NotForDeriving2 "public final class"
+%javamethodmodifiers NotForDeriving1::~NotForDeriving1 "public synchronized final";
+%javamethodmodifiers NotForDeriving2::~NotForDeriving2 "public synchronized final";
+
+#endif
+
+%inline %{
+//#include <iostream>
+struct NotForDeriving1 {
+  void notvirtual() {}
+  ~NotForDeriving1() {
+//    std::cout << "~NotForDeriving1 called" << std::endl;
+  }
+};
+struct NotForDeriving2 {
+  void notvirtual() {}
+#if defined(SWIG)
+%extend {
+  ~NotForDeriving2() {
+//    std::cout << "~NotForDeriving2 called" << std::endl;
+  }
+}
+#endif
+};
+%}