diff --git a/tests-fuzz/Makefile.am b/tests-fuzz/Makefile.am
index 145eaba32..1ffb89631 100644
--- a/tests-fuzz/Makefile.am
+++ b/tests-fuzz/Makefile.am
@@ -29,6 +29,6 @@ BUILT_SOURCES = wrap/main.c
 CLEANFILES = wrap/main.c
 wrap/main.c: Makefile $(top_builddir)/src/utils/knotd/main.c
 	echo '#include "afl-loop.h"' > $@
-	sed -e 's/for (;;)/while (__AFL_LOOP(1000))/' $(top_builddir)/src/utils/knotd/main.c >>$@
+	$(SED) -e 's/for (;;)/while (__AFL_LOOP(1000))/' $(top_srcdir)/src/utils/knotd/main.c >>$@
 
 check-compile: $(check_PROGRAMS)
diff --git a/tests-fuzz/afl-loop.h b/tests-fuzz/afl-loop.h
index 8a8941b77..4db002ef2 100644
--- a/tests-fuzz/afl-loop.h
+++ b/tests-fuzz/afl-loop.h
@@ -1,3 +1,4 @@
+#pragma once
 #ifndef __AFL_COMPILER
 #define __AFL_LOOP(x) (0)
 #endif