diff --git a/src/include/lwip/opt.h b/src/include/lwip/opt.h
index e3f6887a..4c078587 100644
--- a/src/include/lwip/opt.h
+++ b/src/include/lwip/opt.h
@@ -1700,6 +1700,15 @@
 
 #if PPP_SUPPORT
 
+/**
+ * PPP_INPROC_MULTITHREADED==1 call ppp_input() using tcpip_callback().
+ * Set this to 0 if pppos_input() is called inside tcpip_thread or with NO_SYS==1.
+ * Default is 1 for NO_SYS==0 (multithreaded) and 0 for NO_SYS==1 (single-threaded).
+ */
+#ifndef PPP_INPROC_MULTITHREADED
+#define PPP_INPROC_MULTITHREADED (NO_SYS==0)
+#endif
+
 /**
  * LWIP_PPP_API==1: Support PPP API (in pppapi.c)
  */
diff --git a/src/include/netif/ppp/ppp.h b/src/include/netif/ppp/ppp.h
index b005cfda..168d473e 100644
--- a/src/include/netif/ppp/ppp.h
+++ b/src/include/netif/ppp/ppp.h
@@ -50,14 +50,6 @@
 
 #include "vj.h"
 
-/** PPP_INPROC_MULTITHREADED==1 call pppos_input using tcpip_callback().
- * Set this to 0 if pppos_input is called inside tcpip_thread or with NO_SYS==1.
- * Default is 1 for NO_SYS==0 (multithreaded) and 0 for NO_SYS==1 (single-threaded).
- */
-#ifndef PPP_INPROC_MULTITHREADED
-#define PPP_INPROC_MULTITHREADED (NO_SYS==0)
-#endif
-
 
 /*************************
 *** PUBLIC DEFINITIONS ***