[gtk+] Properly check result of g_utf8_get_char_validated()

[Matthias Clasen <matthiasc src gnome org>]

commit 87d36885ac713badc5187f1d26044dbba9e13309
Author: Maks Naumov <maksqwe1 ukr net>
Date:   Sun Jan 11 11:27:37 2015 -0800

    Properly check result of g_utf8_get_char_validated()
    
    g_utf8_get_char_validated() may return -1 or -2
    return type is gunichar(guint32)
    
    Therefore such checks like 'gunichar < 0' or 'gunichar > 0'
    are always 'false' or 'true'(except when gunichar == 0).
    
    Signed-off-by: Maks Naumov <maksqwe1 ukr net>
    
    https://bugzilla.gnome.org/show_bug.cgi?id=742774

 gtk/gtkbuilder.c                 |    2 +-
 modules/input/gtkimcontextthai.c |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtkbuilder.c b/gtk/gtkbuilder.c
index 7b7c166..b0775d2 100644
--- a/gtk/gtkbuilder.c
+++ b/gtk/gtkbuilder.c
@@ -1784,7 +1784,7 @@ gtk_builder_value_from_string (GtkBuilder   *builder,
       gunichar c;
       g_value_init (value, G_TYPE_UINT);
       c = g_utf8_get_char_validated (string, strlen (string));
-      if (c > 0)
+      if (c != 0 && c != (gunichar)-1 && c != (gunichar)-2)
         g_value_set_uint (value, c);
       return TRUE;
     }
diff --git a/modules/input/gtkimcontextthai.c b/modules/input/gtkimcontextthai.c
index 254dfc7..73510c0 100644
--- a/modules/input/gtkimcontextthai.c
+++ b/modules/input/gtkimcontextthai.c
@@ -195,7 +195,7 @@ get_previous_char (GtkIMContextThai *context_thai, gint offset)
       if (offset == 0)
         {
           prev_char = g_utf8_get_char_validated (q, p - q);
-          if (prev_char < 0)
+          if (prev_char == (gunichar)-1 || prev_char == (gunichar)-2)
             prev_char = 0;
         }
       g_free (surrounding);