[libgepub] lib: Fix signedness warnings in GepubDoc

[Daniel Garcia Moreno <danigm src gnome org>]

commit 977eb851857dc37fc5621e635946ef9c692f2c2e
Author: Bastien Nocera <hadess hadess net>
Date:   Thu Jun 22 10:11:57 2017 +0200

    lib: Fix signedness warnings in GepubDoc
    
    https://bugzilla.gnome.org/show_bug.cgi?id=784081

 libgepub/gepub-doc.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/libgepub/gepub-doc.c b/libgepub/gepub-doc.c
index 0c9d48e..0e595bd 100644
--- a/libgepub/gepub-doc.c
+++ b/libgepub/gepub-doc.c
@@ -344,7 +344,7 @@ gepub_doc_get_metadata (GepubDoc *doc, const gchar *mdata)
     mdata_node = gepub_utils_get_element_by_tag (mnode, mdata);
 
     text = xmlNodeGetContent (mdata_node);
-    ret = g_strdup (text);
+    ret = g_strdup ((const char *) text);
     xmlFree (text);
 
     xmlFreeDoc (xdoc);
@@ -532,7 +532,7 @@ gepub_doc_get_text (GepubDoc *doc)
     xmlDoc *xdoc = NULL;
     xmlNode *root_element = NULL;
     GBytes *current;
-    const guchar *data;
+    const gchar *data;
     gsize size;
 
     GList *texts = NULL;
@@ -567,7 +567,7 @@ gepub_doc_get_text_by_id (GepubDoc *doc, const gchar *id)
     xmlDoc *xdoc = NULL;
     xmlNode *root_element = NULL;
     gsize size;
-    const guchar *res;
+    const gchar *res;
     GBytes *contents;
 
     GList *texts = NULL;