diff --git a/skeletons/tests/check-PER.c b/skeletons/tests/check-PER.c
index e0fb72e..12e700c 100644
--- a/skeletons/tests/check-PER.c
+++ b/skeletons/tests/check-PER.c
@@ -1,6 +1,8 @@
-#include <per_support.c>
+#include <stdio.h>
 #include <assert.h>
 
+#include <per_support.h>
+
 static void
 check_per_decoding() {
 	uint8_t buf[] = { 0xB7, 0x19, 0x2F, 0xEE, 0xAD };