--- configure
+++ configure
@@ -21478,6 +21478,7 @@
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
+#include <stdlib.h>
 #include <semaphore.h>
 main () {
   struct s {
@@ -21514,6 +21515,7 @@
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
+#include <stdlib.h>
 main () {
   struct s {
     char a;