typefind: Fix debug category usage

Only register it in one place and use it everywhere from the header. Also make
sure it doesn't clash with the debug category from core.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-base/-/merge_requests/972>

gst/typefind/gsttypefindfunctions.c

@@ -45,9 +45,6 @@
 
 #include "gsttypefindfunctionsplugin.h"
 
-GST_DEBUG_CATEGORY_STATIC (type_find_debug);
-#define GST_CAT_DEFAULT type_find_debug
-
 /* DataScanCtx: helper for typefind functions that scan through data
  * step-by-step, to avoid doing a peek at each and every offset */
 

gst/typefind/gsttypefindfunctionsplugin.c

@@ -30,14 +30,13 @@
 
 #include <gst/gst.h>
 
-GST_DEBUG_CATEGORY_STATIC (type_find_debug);
-#define GST_CAT_DEFAULT type_find_debug
+GST_DEBUG_CATEGORY (type_find_functions_debug);
 
 static gboolean
 plugin_init (GstPlugin * plugin)
 {
   /* can't initialize this via a struct as caps can't be statically initialized */
-  GST_DEBUG_CATEGORY_INIT (type_find_debug, "typefindfunctions",
+  GST_DEBUG_CATEGORY_INIT (type_find_functions_debug, "typefindfunctions",
       GST_DEBUG_FG_GREEN | GST_DEBUG_BG_RED, "generic type find functions");
   /* note: asx/wax/wmx are XML files, asf doesn't handle them */
   /* must use strings, macros don't accept initializers */

gst/typefind/gsttypefindfunctionsplugin.h

@@ -29,6 +29,9 @@
 
 #include <gst/gst.h>
 
+GST_DEBUG_CATEGORY_EXTERN (type_find_functions_debug);
+#define GST_CAT_DEFAULT type_find_functions_debug
+
 /*** plugin initialization ***/
 
 /*RIFF type find declaration */

gst/typefind/gsttypefindfunctionsstartwith.c

@@ -33,9 +33,6 @@
 #include "gsttypefindfunctionsplugin.h"
 #include "gsttypefindfunctionsdata.h"
 
-GST_DEBUG_CATEGORY_STATIC (type_find_debug);
-#define GST_CAT_DEFAULT type_find_debug
-
 static void
 start_with_type_find (GstTypeFind * tf, gpointer private)
 {