[libgit2-glib] diff: options prefix type has changed to const.

[Ignacio Casal Quinteiro <icq src gnome org>]

commit 8bda90af43b795c353a254c5f8edbd72c0ec911d
Author: Ignacio Casal Quinteiro <icq gnome org>
Date:   Sun Dec 16 13:31:54 2012 +0100

    diff: options prefix type has changed to const.

 libgit2-glib/ggit-diff-options.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/libgit2-glib/ggit-diff-options.c b/libgit2-glib/ggit-diff-options.c
index 07b52e6..851974d 100644
--- a/libgit2-glib/ggit-diff-options.c
+++ b/libgit2-glib/ggit-diff-options.c
@@ -92,8 +92,8 @@ ggit_diff_options_free (GgitDiffOptions *diff_options)
 	g_return_if_fail (diff_options != NULL);
 
 	gdiff_options = &diff_options->diff_options;
-	g_free (gdiff_options->old_prefix);
-	g_free (gdiff_options->new_prefix);
+	g_free ((gchar *)gdiff_options->old_prefix);
+	g_free ((gchar *)gdiff_options->new_prefix);
 	git_strarray_free (&gdiff_options->pathspec);
 
 	g_slice_free (GgitDiffOptions, diff_options);