Further build fix
diff --git a/tests/fuzztest/generate_message.c b/tests/fuzztest/generate_message.c
index 51ef83b..1b29dab 100644
--- a/tests/fuzztest/generate_message.c
+++ b/tests/fuzztest/generate_message.c
@@ -11,6 +11,10 @@
#include "alltypes_static.pb.h"
#include "random_data.h"
+#ifndef FUZZTEST_BUFSIZE
+#define FUZZTEST_BUFSIZE 4096
+#endif
+
/* Check that size/count fields do not exceed their max size.
* Otherwise we would have to loop pretty long in generate_message().
* Note that there may still be a few encoding errors from submessages.
