Include <string.h> for the strcmp function.
Submitted upstream: <https://savannah.gnu.org/support/index.php?110800>
diff --git a/sample.c b/sample.c
index 46e620586ca3c05e..a7bc389b3fc14306 100644
--- a/sample.c
+++ b/sample.c
@@ -1,5 +1,6 @@
#include <stdio.h>
#include <stdlib.h>
+#include <string.h>
#include "barcode.h"