diff --git a/src/core/init.c b/src/core/init.c
index 0e17a7a0..6dfda80a 100644
--- a/src/core/init.c
+++ b/src/core/init.c
@@ -60,6 +60,8 @@
 #include "lwip/mld6.h"
 #include "lwip/api.h"
 
+#include "netif/ppp/ppp_opts.h"
+
 /* Compile-time sanity checks for configuration errors.
  * These can be done independently of LWIP_DEBUG, without penalty.
  */
diff --git a/src/include/lwip/memp.h b/src/include/lwip/memp.h
index d7463f2b..e92b4f40 100644
--- a/src/include/lwip/memp.h
+++ b/src/include/lwip/memp.h
@@ -33,6 +33,9 @@
 #ifndef LWIP_HDR_MEMP_H
 #define LWIP_HDR_MEMP_H
 
+/* needed by memp_std.h */
+#include "netif/ppp/ppp_opts.h"
+
 #ifdef __cplusplus
 extern "C" {
 #endif