iphplapi: Include <sys/timeout.h> for OpenBSD/NetBSD.
diff --git a/configure.ac b/configure.ac
index 25e78e8..1a2828d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -354,6 +354,7 @@
 	sys/strtio.h \
 	sys/syscall.h \
 	sys/time.h \
+	sys/timeout.h \
 	sys/times.h \
 	sys/uio.h \
 	sys/un.h \