Mail: Fix gcc4 build.

- Fix typo in forward declaration.
- Add missing include for snprintf.
- Add missing virtual destructor on QueryListener abstract class.

src/apps/mail/Content.h

@@ -61,7 +61,7 @@ class TScrollView;
 class TTextView;
 class BFile;
 class BList;
-class BPopupMenu;
+class BPopUpMenu;
 
 struct text_run_array;
 

src/apps/mail/People.cpp

@@ -6,6 +6,8 @@
 
 #include "People.h"
 
+#include <stdio.h>
+
 #include <Autolock.h>
 #include <Node.h>
 

src/apps/mail/QueryList.cpp

@@ -24,7 +24,15 @@ initQueryLooper()
 }
 
 
-// #pragma mark -
+// #pragma mark - QueryListener
+
+
+QueryListener::~QueryListener()
+{
+}
+
+
+// #pragma mark - QueryList
 
 
 QueryList::QueryList()

src/apps/mail/QueryList.h

@@ -21,6 +21,7 @@ struct QueryList;
 
 class QueryListener {
 public:
+	virtual 				~QueryListener();
 	virtual	void				EntryCreated(QueryList& source,
 									const entry_ref& ref, ino_t node) = 0;
 	virtual	void				EntryRemoved(QueryList& source,