diff --git a/test/regress_thread.c b/test/regress_thread.c
index 15d9d2ac..757f2b2a 100644
--- a/test/regress_thread.c
+++ b/test/regress_thread.c
@@ -33,9 +33,12 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#ifndef WIN32
+#ifdef _EVENT_HAVE_UNISTD_H
 #include <unistd.h>
 #endif
+#ifdef _EVENT_HAVE_SYS_WAIT_H
+#include <sys/wait.h>
+#endif
 
 #ifdef _EVENT_HAVE_PTHREADS
 #include <pthread.h>