[gegl] json: add prototype for gegl_op_json_register_type

[Øyvind Kolås <ok src gnome org>]

commit 417d7624d26c0aa1307a30acd57d2ff51a2cba0f
Author: Øyvind Kolås <pippin gimp org>
Date:   Wed Apr 12 01:58:14 2017 +0200

    json: add prototype for gegl_op_json_register_type

 operations/core/json.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/operations/core/json.c b/operations/core/json.c
index 04c0987..64f0d85 100644
--- a/operations/core/json.c
+++ b/operations/core/json.c
@@ -613,6 +613,9 @@ const GeglModuleInfo  * gegl_module_query    (GTypeModule *module);
 #ifdef GEGL_OP_BUNDLE
 
 G_MODULE_EXPORT void
+gegl_op_json_register_type (GTypeModule *module);
+
+G_MODULE_EXPORT void
 gegl_op_json_register_type (GTypeModule *module)
 {
 #else