sched_backtrace: define sched_dumpstack when not enable SCHED_BACKTRACE

Before directly use sched_backtrace() with SCHED_BACKTRACE disable will
lead compile error, this commit avoid this problem by define
sched_backtrace to 0 when CONFIG_SCHED_BACKTRACE not enable.

Signed-off-by: Bowen Wang <wangbowen6@xiaomi.com>

include/execinfo.h

@@ -33,20 +33,9 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
-#if defined(CONFIG_SCHED_BACKTRACE)
-
-/* Store up to SIZE return address of the current back trace in
- * ARRAY and return the exact number of values stored.
- */
-
-#  define backtrace(buffer, size) sched_backtrace(_SCHED_GETTID(), \
-                                                 buffer, size, 0)
-#  define dump_stack()            sched_dumpstack(_SCHED_GETTID())
-
-#else
-#  define backtrace(buffer, size) 0
-#  define dump_stack()
-#endif
+#define backtrace(buffer, size) sched_backtrace(_SCHED_GETTID(), \
+                                                buffer, size, 0)
+#define dump_stack()            sched_dumpstack(_SCHED_GETTID())
 
 /****************************************************************************
  * Public Function Prototypes

include/sched.h

@@ -267,8 +267,13 @@ bool   sched_idletask(void);
 
 /* Task Backtrace */
 
+#ifdef CONFIG_SCHED_BACKTRACE
 int    sched_backtrace(pid_t tid, FAR void **buffer, int size, int skip);
 void   sched_dumpstack(pid_t tid);
+#else
+#  define sched_backtrace(tid, buffer, size, skip) 0
+#  define sched_dumpstack(tid)
+#endif
 
 #undef EXTERN
 #if defined(__cplusplus)