core/thread: add thread_getname() dummy available without DEVELHELP

core/include/thread.h

@@ -447,10 +447,11 @@ char *thread_stack_init(thread_task_func_t task_func, void *arg, void *stack_sta
  */
 void thread_add_to_list(list_node_t *list, thread_t *thread);
 
-#ifdef DEVELHELP
 /**
  * @brief Returns the name of a process
  *
+ * @note when compiling without DEVELHELP, this *always* returns NULL!
+ *
  * @param[in] pid   the PID of the thread to get the name from
  *
  * @return          the threads name
@@ -458,6 +459,7 @@ void thread_add_to_list(list_node_t *list, thread_t *thread);
  */
 const char *thread_getname(kernel_pid_t pid);
 
+#ifdef DEVELHELP
 /**
  * @brief Measures the stack usage of a stack
  *

core/thread.c

@@ -44,13 +44,16 @@ int thread_getstatus(kernel_pid_t pid)
     return t ? (int) t->status : STATUS_NOT_FOUND;
 }
 
-#ifdef DEVELHELP
 const char *thread_getname(kernel_pid_t pid)
 {
+#ifdef DEVELHELP
     volatile thread_t *t = thread_get(pid);
     return t ? t->name : NULL;
-}
+#else
+    (void)pid;
+    return NULL;
 #endif
+}
 
 void thread_sleep(void)
 {