diff --git a/Include/internal/pycore_pythread.h b/Include/internal/pycore_pythread.h
index 4aeb285b89a..f53921494c1 100644
--- a/Include/internal/pycore_pythread.h
+++ b/Include/internal/pycore_pythread.h
@@ -33,7 +33,7 @@ extern "C" {
 # endif /* _POSIX_THREADS */
 #endif /* _POSIX_THREADS */
 
-#if defined(_POSIX_THREADS) && !defined(HAVE_PTHREAD_STUBS)
+#if defined(_POSIX_THREADS) || defined(HAVE_PTHREAD_STUBS)
 # define _USE_PTHREADS
 #endif
 
diff --git a/Python/thread_pthread.h b/Python/thread_pthread.h
index ae312e987bd..76d6f3bcdf9 100644
--- a/Python/thread_pthread.h
+++ b/Python/thread_pthread.h
@@ -132,7 +132,8 @@ init_condattr(void)
     if (pthread_condattr_setclock(&ca, CLOCK_MONOTONIC) == 0) {
         condattr_monotonic = &ca;  // Use monotonic clock
     }
-#endif
+# undef ca
+#endif  // CONDATTR_MONOTONIC
 }
 
 int