diff --git a/src/wdt.c b/src/wdt.c
index 60a5fd4..19d36c3 100644
--- a/src/wdt.c
+++ b/src/wdt.c
@@ -25,7 +25,7 @@
  * It relies on timer_create() and timer_settime() which are only available in
  * this case.
  */
-#if defined(USE_THREAD) && (_POSIX_TIMERS > 0) && defined(_POSIX_THREAD_CPUTIME)
+#if defined(USE_THREAD) && defined(USE_RT) && (_POSIX_TIMERS > 0) && defined(_POSIX_THREAD_CPUTIME)
 
 /* We'll deliver SIGALRM when we've run out of CPU as it's not intercepted by
  * gdb by default.