diff --git a/Backends/Kinc-HL/hl/libs/fmt/fmt_crypto.c b/Backends/Kinc-HL/hl/libs/fmt/fmt_crypto.c
index 39ee57a46..94347b67c 100644
--- a/Backends/Kinc-HL/hl/libs/fmt/fmt_crypto.c
+++ b/Backends/Kinc-HL/hl/libs/fmt/fmt_crypto.c
@@ -3,6 +3,9 @@
 #define HL_NAME(n) fmt_##n
 #include <hl.h>
 
+unsigned long adler32(unsigned long adler, const unsigned char *buf, unsigned int len);
+unsigned long crc32(unsigned long crc, const unsigned char *buf, unsigned int len);
+
 /* ------------------------------------------------- CRYPTO --------------------------------------------------- */
 
 typedef unsigned int uint32;