[gegl] panorama-projection: re-enable autothreading

[Øyvind Kolås <ok src gnome org>]

commit 1008a506a8c9e43eb9bc0415c3612bbe50c840f6
Author: Øyvind Kolås <pippin gimp org>
Date:   Thu May 3 22:39:55 2018 +0200

    panorama-projection: re-enable autothreading
    
    The on demand COW of tiles from preceding commit makes auto-
    threading faster than single threaded rendering.

 operations/common/panorama-projection.c |    4 +---
 1 files changed, 1 insertions(+), 3 deletions(-)
---
diff --git a/operations/common/panorama-projection.c b/operations/common/panorama-projection.c
index ef609c5..6fab1e7 100644
--- a/operations/common/panorama-projection.c
+++ b/operations/common/panorama-projection.c
@@ -593,9 +593,7 @@ gegl_op_class_init (GeglOpClass *klass)
 
   filter_class->process = process;
   operation_class->prepare = prepare;
-  operation_class->threaded = FALSE; /* XXX: figure out a way to make
-multi-threaded access to cache-work, and add a flag to operation_class about
-not wanting duplicated inputs */
+  operation_class->threaded = TRUE;
   operation_class->get_bounding_box = get_bounding_box;
   operation_class->get_required_for_output = get_required_for_output;