diff --git a/tests/fuzz/main.c b/tests/fuzz/main.c
index 2776dea..1c0c4d7 100644
--- a/tests/fuzz/main.c
+++ b/tests/fuzz/main.c
@@ -2,6 +2,8 @@
 #include <stdint.h>
 #include <stdlib.h>
 
+int LLVMFuzzerTestOneInput(uint8_t const *buf, size_t len);
+
 #ifdef  __AFL_COMPILER
 
 int main(void) {