Added several more missing virtual keywords

src/draft.h

@@ -86,7 +86,7 @@ public:
     if (! args.empty())
       parse_args(args);
   }
-  ~draft_t() {
+  virtual ~draft_t() {
     TRACE_DTOR(draft_t);
   }
 

src/expr.h

@@ -87,7 +87,7 @@ public:
     parse(in, flags);
   }
 
-  ~expr_t() throw() {
+  virtual ~expr_t() {
     TRACE_DTOR(expr_t);
   }
 

src/exprbase.h

@@ -92,7 +92,7 @@ public:
   {
     TRACE_CTOR(expr_base_t, "scope_t *");
   }
-  virtual ~expr_base_t() throw() {
+  virtual ~expr_base_t() {
     TRACE_DTOR(expr_base_t);
   }
 

src/format.h

@@ -132,7 +132,7 @@ public:
     if (! _str.empty())
       parse_format(_str);
   }
-  ~format_t() {
+  virtual ~format_t() {
     TRACE_DTOR(format_t);
   }
 

src/predicate.h

@@ -75,7 +75,7 @@ public:
     : expr_t(in, flags), what_to_keep(_what_to_keep) {
     TRACE_CTOR(predicate_t, "std::istream&, keep_details_t, parse_flags_t");
   }
-  ~predicate_t() throw() {
+  virtual ~predicate_t() {
     TRACE_DTOR(predicate_t);
   }
 

src/query.h

@@ -276,7 +276,7 @@ public:
     if (! args.empty())
       parse_args(args);
   }
-  ~query_t() throw() {
+  virtual ~query_t() {
     TRACE_DTOR(query_t);
   }