Add 64-bit integers support to wxConfig

Serialize them to strings in wxFileConfig, just as we always did for
long, but use wxRegKey support for storing them directly to the registry
in wxRegConfig.

interface/wx/config.h

@@ -549,6 +549,29 @@ public:
     */
     bool Read(const wxString& key, long* l,
               long defaultVal) const;
+    /**
+        Reads a 64-bit long long value, returning @true if the value was found.
+        If the value was not found, @a ll is not changed.
+
+        @since 3.1.5
+
+        @beginWxPerlOnly
+        Not supported by wxPerl.
+        @endWxPerlOnly
+    */
+    bool Read(const wxString& key, wxLongLong_t* ll) const;
+    /**
+        Reads a 64-bit long long value, returning @true if the value was found.
+        If the value was not found, @a defaultVal is used instead.
+
+        @since 3.1.5
+
+        @beginWxPerlOnly
+        Not supported by wxPerl.
+        @endWxPerlOnly
+    */
+    bool Read(const wxString& key, wxLongLong_t* ll,
+              wxLongLong_t defaultVal) const;
     /**
         Reads a double value, returning @true if the value was found. If the
         value was not found, @a d is not changed.
@@ -662,6 +685,14 @@ public:
     */
     long ReadLong(const wxString& key, long defaultVal) const;
 
+    /**
+        Reads a 64-bit long long value from the key and returns it. @a
+        defaultVal is returned if the key is not found.
+
+        @since 3.1.5
+    */
+    wxLongLong_t ReadLongLong(const wxString& key, wxLongLong_t defaultVal) const;
+
     /**
         Reads a value of type T (for which the function wxFromString() must be
         defined) from the key and returns it. @a defaultVal is returned if the
@@ -678,6 +709,13 @@ public:
         Writes the long value to the config file and returns @true on success.
     */
     bool Write(const wxString& key, long value);
+    /**
+        Writes the 64-bit long long value to the config file and returns @true
+        on success.
+
+        @since 3.1.5
+    */
+    bool Write(const wxString& key, wxLongLong_t value);
     /**
         Writes the double value to the config file and returns @true on
         success.