[glib] make *_get_instance_private const-compliant

[Marc-Antoine Perennou <marcop src gnome org>]

commit a3a9664ed202303b899ca55625877542309d1a1f
Author: Marc-Antoine Perennou <Marc-Antoine Perennou com>
Date:   Sat Nov 9 12:09:20 2013 +0900

    make *_get_instance_private const-compliant
    
    This is pure read-only access to an external struct
    so void warnings for people calling it from const
    contexts such as accessors
    
    https://bugzilla.gnome.org/show_bug.cgi?id=745068
    
    Signed-off-by: Marc-Antoine Perennou <Marc-Antoine Perennou com>

 gobject/gtype.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gobject/gtype.h b/gobject/gtype.h
index fadaadb..68bc051 100644
--- a/gobject/gtype.h
+++ b/gobject/gtype.h
@@ -1938,7 +1938,7 @@ _G_DEFINE_TYPE_EXTENDED_CLASS_INIT(TypeName, type_name) \
 \
 G_GNUC_UNUSED \
 static inline gpointer \
-type_name##_get_instance_private (TypeName *self) \
+type_name##_get_instance_private (const TypeName *self) \
 { \
   return (G_STRUCT_MEMBER_P (self, TypeName##_private_offset)); \
 } \