Pacify -Wnon-virtual-dtor.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166270 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/MC/MCParser/MCAsmParser.h

@@ -34,6 +34,7 @@ class Twine;
 /// MCAsmParserSemaCallback - Generic Sema callback for assembly parser.
 class MCAsmParserSemaCallback {
 public:
+  virtual ~MCAsmParserSemaCallback(); 
   virtual void *LookupInlineAsmIdentifier(StringRef Name, void *Loc,
                                           unsigned &Size) = 0;
 };