diff --git a/src/include/lwip/arch.h b/src/include/lwip/arch.h
index d8b13a57..447d90bb 100644
--- a/src/include/lwip/arch.h
+++ b/src/include/lwip/arch.h
@@ -73,12 +73,16 @@
 /** Platform specific diagnostic output */
 #ifndef LWIP_PLATFORM_DIAG
 #define LWIP_PLATFORM_DIAG(x)	do {printf x;} while(0)
+#include <stdio.h>
+#include <stdlib.h>
 #endif
 
 /** Platform specific assertion handling */
 #ifndef LWIP_PLATFORM_ASSERT
 #define LWIP_PLATFORM_ASSERT(x) do {printf("Assertion \"%s\" failed at line %d in %s\n", \
                                      x, __LINE__, __FILE__); fflush(NULL); abort();} while(0)
+#include <stdio.h>
+#include <stdlib.h>
 #endif
 
 /** Define this to 1 in arch/cc.h of your port if you do not want to