[gegl] webp: Do not pass warning strings directly to printf function

[Øyvind Kolås <ok src gnome org>]

commit ee79239ac319d9cb70dee8370d7d91ede59175e2
Author: Martin Blanchard <tchaik gmx com>
Date:   Sun Mar 20 21:50:41 2016 +0100

    webp: Do not pass warning strings directly to printf function

 operations/external/webp-load.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/operations/external/webp-load.c b/operations/external/webp-load.c
index 72412a4..1dece66 100644
--- a/operations/external/webp-load.c
+++ b/operations/external/webp-load.c
@@ -100,7 +100,7 @@ read_from_stream (GInputStream *stream,
                                      NULL, &error);
   if (!success || error != NULL)
     {
-      g_warning (error->message);
+      g_warning ("%s", error->message);
       g_error_free (error);
       return -1;
     }
@@ -130,7 +130,7 @@ decode_from_stream (GInputStream *stream,
                                          NULL, &error);
       if (!success || error != NULL)
         {
-          g_warning (error->message);
+          g_warning ("%s", error->message);
           g_error_free (error);
           return -1;
         }
@@ -208,7 +208,7 @@ prepare (GeglOperation *operation)
       p->stream = gegl_gio_open_input_stream (o->uri, o->path, &p->file, &error);
       if (p->stream == NULL)
         {
-          g_warning (error->message);
+          g_warning ("%s", error->message);
           g_error_free (error);
           cleanup (operation);
           return;