2 files changed, 2 insertions, 3 deletions
diff --git a/validation/backend/hello.c b/validation/backend/hello.c
index b0e514be..eb89846f 100644
--- a/validation/backend/hello.c
+++ b/validation/backend/hello.c
@@ -1,4 +1,4 @@
-#include <stdio.h>
+int puts(const char *s);
 
 int main(int argc, char *argv[])
 {
diff --git a/validation/backend/sum.c b/validation/backend/sum.c
index fa51120e..38ebf41e 100644
--- a/validation/backend/sum.c
+++ b/validation/backend/sum.c
@@ -1,5 +1,4 @@
-#include <stdio.h>
-#include <stdlib.h>
+int printf(const char * fmt, ...);
 
 static int sum(int n)
 {