libyang CHANGE headers includes cleanup using include-what-you-use tool (#1098)

diff --git a/src/printer.h b/src/printer.h
index 00d34e3..f9ac3af 100644
--- a/src/printer.h
+++ b/src/printer.h
@@ -15,8 +15,11 @@
 #ifndef LY_PRINTER_H_
 #define LY_PRINTER_H_
 
+#include <stdio.h>
 #include <unistd.h>
 
+#include "log.h"
+
 /**
  * @brief Printer output structure specifying where the data are printed.
  */