Bail out of sys/queue.h lacks STAILQ

diff --git a/interface.h b/interface.h
index 9c42ec6fe31e0e87a9fcebccc240d3805e20a49f..3f42ef5cb73a2a44f5f13c6537645b5b7d01a1ca 100644 (file)
--- a/interface.h
+++ b/interface.h
@@ -84,6 +84,10 @@
 # define IN_LINKLOCAL(addr) ((addr & IN_CLASSB_NET) == LINKLOCAL_ADDR)
 #endif
 
+#ifndef STAILQ_ENTRY
+# error "your sys/queue.h is too old and lacks STAILQ"
+#endif
+
 #define NSTAILQ_FOREACH(var, head, field) \
                if (head) STAILQ_FOREACH (var, head, field)