1 files changed, 1 insertions, 0 deletions
diff --git a/os/src/free.c b/os/src/free.c
index f2d1fe5..d80aff2 100644
--- a/os/src/free.c
+++ b/os/src/free.c
@@ -1,4 +1,5 @@
 #include <reent.h>
+#include <malloc.h>
 
 void free(void * ptr) {
     _free_r(_impure_ptr, ptr);