cleanup the headers

Make some cleanup around the headers.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
diff --git a/display.c b/display.c
index 92fc02a..3c79737 100644
--- a/display.c
+++ b/display.c
@@ -13,6 +13,10 @@
  *       - initial API and implementation
  *******************************************************************************/
 
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <ncurses.h>
 #include "powerdebug.h"
 #include "regulator.h"
 #include "display.h"