--- configure
+++ configure
@@ -20518,8 +20518,9 @@
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
+#include <stdlib.h>
 #include <semaphore.h>
-	main () {
+	int main () {
 		sem_t s;
 		exit(sem_init(&s,0,0));
 		}
@@ -21263,8 +21264,9 @@
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
+#include <stdlib.h>
 #include <unistd.h>
-    main () {
+    int main () {
     exit(!(sizeof(off_t) == 8));
   }
 _ACEOF
@@ -21478,8 +21480,9 @@
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
+#include <stdlib.h>
 #include <semaphore.h>
-main () {
+int main () {
   struct s {
     char a;
     union { long long x; sem_t y; } b;
@@ -21514,7 +21517,8 @@
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-main () {
+#include <stdlib.h>
+int main () {
   struct s {
     char a;
     double b;