diff --git a/lib/libc_r/uthread/uthread_sigwait.c b/lib/libc_r/uthread/uthread_sigwait.c
index 96a1e159570b..e08b2987148a 100644
--- a/lib/libc_r/uthread/uthread_sigwait.c
+++ b/lib/libc_r/uthread/uthread_sigwait.c
@@ -32,6 +32,8 @@
  * $FreeBSD$
  */
 #include <signal.h>
+#include <sys/param.h>
+#include <sys/signalvar.h>
 #include <errno.h>
 #ifdef _THREAD_SAFE
 #include <pthread.h>
diff --git a/lib/libkse/thread/thr_sigwait.c b/lib/libkse/thread/thr_sigwait.c
index 96a1e159570b..e08b2987148a 100644
--- a/lib/libkse/thread/thr_sigwait.c
+++ b/lib/libkse/thread/thr_sigwait.c
@@ -32,6 +32,8 @@
  * $FreeBSD$
  */
 #include <signal.h>
+#include <sys/param.h>
+#include <sys/signalvar.h>
 #include <errno.h>
 #ifdef _THREAD_SAFE
 #include <pthread.h>
diff --git a/lib/libpthread/thread/thr_sigwait.c b/lib/libpthread/thread/thr_sigwait.c
index 96a1e159570b..e08b2987148a 100644
--- a/lib/libpthread/thread/thr_sigwait.c
+++ b/lib/libpthread/thread/thr_sigwait.c
@@ -32,6 +32,8 @@
  * $FreeBSD$
  */
 #include <signal.h>
+#include <sys/param.h>
+#include <sys/signalvar.h>
 #include <errno.h>
 #ifdef _THREAD_SAFE
 #include <pthread.h>