diff --git a/src/libsodium/include/sodium/crypto_kdf_blake2b.h b/src/libsodium/include/sodium/crypto_kdf_blake2b.h
index 3ae47dd3..489c7c20 100644
--- a/src/libsodium/include/sodium/crypto_kdf_blake2b.h
+++ b/src/libsodium/include/sodium/crypto_kdf_blake2b.h
@@ -3,8 +3,8 @@
 
 #include <stddef.h>
 #include <stdint.h>
+#include <stdlib.h>
 
-#include "crypto_kdf_blake2b.h"
 #include "export.h"
 
 #ifdef __cplusplus