Some cleanups for compilation with GCC 4.0.0 to remove warnings:

* Use C++ style casts, not C style casts
* Abstract base classes should have virtual destructor.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22057 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Assembly/AsmAnnotationWriter.h

@@ -27,6 +27,8 @@ class Instruction;
 
 struct AssemblyAnnotationWriter {
 
+  virtual ~AssemblyAnnotationWriter();
+
   // emitFunctionAnnot - This may be implemented to emit a string right before
   // the start of a function.
   virtual void emitFunctionAnnot(const Function *F, std::ostream &OS) {}