[gegl-qt] Build: Fix build with babl 0.1.7+git after constification

[Jon Nordby <jonnor src gnome org>]

commit f0bc8111d89fe4f29bdfda9ac3bad4eae10939af
Author: Jon Nordby <jononor gmail com>
Date:   Tue Mar 27 12:58:26 2012 +0200

    Build: Fix build with babl 0.1.7+git after constification
    
    bablfishes are meant to be const starting from babl commit
    http://git.gnome.org/browse/babl/commit/?id=afd9b27918e766858724b25ce427af66ed46db2b

 gegl-qt/internal/nodeviewimplementation.cpp |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gegl-qt/internal/nodeviewimplementation.cpp b/gegl-qt/internal/nodeviewimplementation.cpp
index e0364ec..446ddcd 100644
--- a/gegl-qt/internal/nodeviewimplementation.cpp
+++ b/gegl-qt/internal/nodeviewimplementation.cpp
@@ -319,7 +319,7 @@ NodeViewImplementation::paint(QPainter *painter, const QRectF & viewRect)
     guchar *buffer = NULL;
     GeglRectangle roi;
 
-    Babl *format = babl_format("B'aG'aR'aA u8");
+    const Babl *format = babl_format("B'aG'aR'aA u8");
 
     if (!format) {
         qCritical() << "Unknown Babl format";