[gegl] png-save: store sRGB meta-data

[Øyvind Kolås <ok src gnome org>]

commit 2f21f16d587768fff5bf9d93d6f58cd163859be2
Author: Øyvind Kolås <pippin gimp org>
Date:   Thu Sep 14 00:02:25 2017 +0200

    png-save: store sRGB meta-data

 operations/external/png-save.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/operations/external/png-save.c b/operations/external/png-save.c
index 8ed0ec6..9642ad5 100644
--- a/operations/external/png-save.c
+++ b/operations/external/png-save.c
@@ -146,6 +146,7 @@ export_png (GeglOperation       *operation,
       white.red = 0xff;
       white.blue = 0xff;
       white.green = 0xff;
+      png_set_sRGB_gAMA_and_cHRM (png, info, PNG_sRGB_INTENT_RELATIVE);
     }
   else
     white.gray = 0xff;