[easytag] Fix const usage for id3_tag structure parameters

[David King <davidk src gnome org>]

commit 7b78806e2adee1c4ff500005adde6b481235c8d9
Author: David King <amigadave amigadave com>
Date:   Sat Jan 12 08:36:36 2013 +0000

    Fix const usage for id3_tag structure parameters
    
    The structs are passed to id3_tag_render(), which accepts a const
    pointer to a non-const id3_tag.

 src/id3v24_tag.c |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)
---
diff --git a/src/id3v24_tag.c b/src/id3v24_tag.c
index 086e10f..265d01f 100644
--- a/src/id3v24_tag.c
+++ b/src/id3v24_tag.c
@@ -82,7 +82,8 @@ static struct id3_frame *Id3tag_find_and_create_frame    (struct id3_tag *tag, c
 static struct id3_frame *Id3tag_find_and_create_txxframe (struct id3_tag *tag, const gchar *param1);
 static int    id3taglib_set_field       (struct id3_frame *frame, const gchar *str, enum id3_field_type type, int num, int clear, int id3v1);
 static int    etag_set_tags             (const gchar *str, const char *frame_name, enum id3_field_type field_type, struct id3_tag *v1tag, struct id3_tag *v2tag, gboolean *strip_tags);
-static int    etag_write_tags           (const gchar *filename, const struct id3_tag *v1tag, const struct id3_tag *v2tag, gboolean strip_tags);
+static int etag_write_tags (const gchar *filename, struct id3_tag const *v1tag,
+                            struct id3_tag const *v2tag, gboolean strip_tags);
 
 /*************
  * Functions *
@@ -1353,8 +1354,8 @@ etag_set_tags (const gchar *str,
 
 static int
 etag_write_tags (const gchar *filename, 
-                 const struct id3_tag *v1tag, 
-                 const struct id3_tag *v2tag, 
+                 struct id3_tag const *v1tag,
+                 struct id3_tag const *v2tag,
                  gboolean strip_tags)
 {
     id3_byte_t *v1buf, *v2buf;