--- libmalloc/libmalloc-521.100.59/tests/madvise.c
+++ libmalloc/libmalloc-409.81.2/tests/madvise.c
@@ -10,6 +10,9 @@
 #include "platform.h"
 #include "nano_zone_common.h"
 #include "nano_zone.h"
+
+extern int
+malloc_engaged_nano(void);
 
 #define T_EXPECT_BYTES(p, len, byte, msg, ...) do { \
 	char *_p = (char *)(p); \