[gnome-builder] xml: fix -Wsign-compare warning

[Christian Hergert <chergert src gnome org>]

commit ea9b31b4431ff800187d8e0bb2fd95edcc1abcf9
Author: Christian Hergert <chergert redhat com>
Date:   Tue Feb 28 12:40:12 2017 -0800

    xml: fix -Wsign-compare warning

 contrib/xml/xml-reader.c |    2 +-
 contrib/xml/xml-reader.h |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/contrib/xml/xml-reader.c b/contrib/xml/xml-reader.c
index 3e783a7..0498d07 100644
--- a/contrib/xml/xml-reader.c
+++ b/contrib/xml/xml-reader.c
@@ -266,7 +266,7 @@ xml_reader_load_from_file (XmlReader     *reader,
 gboolean
 xml_reader_load_from_data (XmlReader   *reader,
                            const gchar *data,
-                           gsize        length,
+                           gssize       length,
                            const gchar *uri,
                            const gchar *encoding)
 {
diff --git a/contrib/xml/xml-reader.h b/contrib/xml/xml-reader.h
index cfdfa53..800def9 100644
--- a/contrib/xml/xml-reader.h
+++ b/contrib/xml/xml-reader.h
@@ -48,7 +48,7 @@ gboolean              xml_reader_load_from_file          (XmlReader     *reader,
                                                           GError       **error);
 gboolean              xml_reader_load_from_data          (XmlReader     *reader,
                                                           const gchar   *data,
-                                                          gsize          length,
+                                                          gssize         length,
                                                           const gchar   *uri,
                                                           const gchar   *encoding);
 gboolean              xml_reader_load_from_stream        (XmlReader     *reader,