diff --git a/configure.in b/configure.in
index f4c6b13..a6ebad8 100644
--- a/configure.in
+++ b/configure.in
@@ -89,6 +89,16 @@ ETR_UNION_SEMUN
 
 dnl sched_setscheduler on OpenBSD
 AC_CHECK_FUNCS(sched_setscheduler)
+AC_CHECK_LIB(posix4, sched_setscheduler)
+AC_CHECK_LIB(posix4, sched_setscheduler, [
+      AC_DEFINE([HAVE_SCHED_SETSCHEDULER],[1],
+      [Define if you have the sched_setscheduler function.])
+])
+AC_CHECK_LIB(rt, sched_setscheduler)
+AC_CHECK_LIB(rt, sched_setscheduler, [
+      AC_DEFINE([HAVE_SCHED_SETSCHEDULER],[1],
+      [Define if you have the sched_setscheduler function.])
+])
 
 dnl i386_get_ioperm on NetBSD&OpenBSD
 AC_CHECK_LIB(i386, i386_get_ioperm)