Fix 'gcc -flto' builds for unittest binaries (undefined reference to

`typeinfo for llvm:🆑:GenericOptionValue').

Remove an "anchor" method for an abstract class. (This does not
increase the number of vtables.)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@183830 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/CommandLine.h

@@ -350,8 +350,6 @@ struct cat {
 struct GenericOptionValue {
   virtual ~GenericOptionValue() {}
   virtual bool compare(const GenericOptionValue &V) const = 0;
-private:
-  virtual void anchor();
 };
 
 template<class DataType> struct OptionValue;