gnrc_pktdump: make pid global

sys/include/net/gnrc/pktdump.h

@@ -50,12 +50,9 @@ extern "C" {
 #endif
 
 /**
- * @brief   Get the PID of the pktdump thread
- *
- * @return  PID of the pktdump thread
- * @return  @ref KERNEL_PID_UNDEF if not initialized
+ * @brief   The PID of the pktdump thread
  */
-kernel_pid_t gnrc_pktdump_getpid(void);
+extern kernel_pid_t gnrc_pktdump_pid;
 
 /**
  * @brief   Start the packet dump thread and listening for incoming packets

sys/net/gnrc/pktdump/gnrc_pktdump.c

@@ -36,7 +36,7 @@
 /**
  * @brief   PID of the pktdump thread
  */
-static kernel_pid_t _pid = KERNEL_PID_UNDEF;
+kernel_pid_t gnrc_pktdump_pid = KERNEL_PID_UNDEF;
 
 /**
  * @brief   Stack for the pktdump thread
@@ -154,17 +154,12 @@ static void *_eventloop(void *arg)
     return NULL;
 }
 
-kernel_pid_t gnrc_pktdump_getpid(void)
-{
-    return _pid;
-}
-
 kernel_pid_t gnrc_pktdump_init(void)
 {
-    if (_pid == KERNEL_PID_UNDEF) {
-        _pid = thread_create(_stack, sizeof(_stack), GNRC_PKTDUMP_PRIO,
+    if (gnrc_pktdump_pid == KERNEL_PID_UNDEF) {
+        gnrc_pktdump_pid = thread_create(_stack, sizeof(_stack), GNRC_PKTDUMP_PRIO,
                              THREAD_CREATE_STACKTEST,
                              _eventloop, NULL, "pktdump");
     }
-    return _pid;
+    return gnrc_pktdump_pid;
 }