plugin api: convert GeanyFiletype to GBoxed internally

GeanyObject signals require GTypes to be gobject-introspection compatible.

src/filetypes.c

@@ -1585,3 +1585,15 @@ gboolean filetype_get_comment_open_close(const GeanyFiletype *ft, gboolean singl
 
 	return !EMPTY(*co);
 }
+
+static void        *copy_(void *src) { return src; }
+static void         free_(void *doc) { }
+
+/** @gironly
+ * Gets the GType of GeanyFiletype
+ *
+ * @return the GeanyFiletype type */
+GEANY_API_SYMBOL
+GType filetype_get_type (void);
+
+G_DEFINE_BOXED_TYPE(GeanyFiletype, filetype, copy_, free_);

src/filetypes.h

@@ -186,6 +186,9 @@ const gchar *filetypes_get_display_name(GeanyFiletype *ft);
 
 const GSList *filetypes_get_sorted_by_name(void);
 
+#define GEANY_TYPE_FILETYPE (filetype_get_type())
+
+GType filetype_get_type (void);
 
 #ifdef GEANY_PRIVATE