counters: use a dedicated type for global counters

Type isn't used by any callers right now.

src/counters.c

@@ -1063,11 +1063,12 @@ StatsCounterMaxId StatsRegisterMaxCounter(const char *name, struct ThreadVars_ *
  * \retval id Counter id for the newly registered counter, or the already
  *            present counter
  */
-uint16_t StatsRegisterGlobalCounter(const char *name, uint64_t (*Func)(void))
+StatsCounterGlobalId StatsRegisterGlobalCounter(const char *name, uint64_t (*Func)(void))
 {
+    StatsCounterGlobalId s = { .id = 0 };
 #if defined (UNITTESTS) || defined (FUZZ)
     if (stats_ctx == NULL)
-        return 0;
+        return s;
 #else
     BUG_ON(stats_ctx == NULL);
 #endif
@@ -1075,7 +1076,8 @@ uint16_t StatsRegisterGlobalCounter(const char *name, uint64_t (*Func)(void))
             &(stats_ctx->global_counter_ctx),
             STATS_TYPE_FUNC,
             Func);
-    return id;
+    s.id = id;
+    return s;
 }
 
 typedef struct CountersIdType_ {

src/counters.h

@@ -38,6 +38,10 @@ typedef struct StatsCounterMaxId {
     uint16_t id;
 } StatsCounterMaxId;
 
+typedef struct StatsCounterGlobalId {
+    uint16_t id;
+} StatsCounterGlobalId;
+
 /**
  * \brief Container to hold the counter variable
  */
@@ -129,7 +133,7 @@ void StatsReleaseResources(void);
 uint16_t StatsRegisterCounter(const char *, struct ThreadVars_ *);
 StatsCounterAvgId StatsRegisterAvgCounter(const char *, struct ThreadVars_ *);
 StatsCounterMaxId StatsRegisterMaxCounter(const char *, struct ThreadVars_ *);
-uint16_t StatsRegisterGlobalCounter(const char *cname, uint64_t (*Func)(void));
+StatsCounterGlobalId StatsRegisterGlobalCounter(const char *cname, uint64_t (*Func)(void));
 
 /* functions used to update local counter values */
 void StatsAddUI64(struct ThreadVars_ *, uint16_t, uint64_t);