[gegl] ff-save: move a static flag to private data

[Øyvind Kolås <ok src gnome org>]

commit 14d484f187e1e4a39c2cd6468ea7ac079d596afc
Author: Øyvind Kolås <pippin gimp org>
Date:   Tue May 9 23:06:47 2017 +0200

    ff-save: move a static flag to private data
    
    This makes gegl:ff-save possible to use in applications saving many different
    container types.

 operations/external/ff-save.c |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)
---
diff --git a/operations/external/ff-save.c b/operations/external/ff-save.c
index 27c4aaa..f181772 100644
--- a/operations/external/ff-save.c
+++ b/operations/external/ff-save.c
@@ -130,6 +130,8 @@ typedef struct
   long      audio_read_pos;
   
   int       next_apts;
+
+  int       file_inited;
 } Priv;
 
 static void
@@ -970,7 +972,6 @@ process (GeglOperation       *operation,
 {
   GeglProperties *o = GEGL_PROPERTIES (operation);
   Priv *p = (Priv*)o->user_data;
-  static gint     inited = 0;
 
   g_assert (input);
 
@@ -982,10 +983,10 @@ process (GeglOperation       *operation,
   p->height = result->height;
   p->input = input;
 
-  if (!inited)
+  if (!p->file_inited)
     {
       tfile (o);
-      inited = 1;
+      p->file_inited = 1;
     }
 
   write_video_frame (o, p->oc, p->video_st);