diff --git a/configure.ac b/configure.ac
index fd29a0f..a1b059f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -56,6 +56,7 @@
 AC_CHECK_HEADERS([netinet/in.h])
 AC_CHECK_HEADERS([pthread.h])
 AC_CHECK_HEADERS([stddef.h])
+AC_CHECK_HEADERS([stdlib.h])
 AC_CHECK_HEADERS([sys/socket.h])
 AC_CHECK_HEADERS([sys/time.h])
 AC_CHECK_HEADERS([unistd.h])