Fix build on case-sensitive filesystems.
--- commands.c.orig	2002-11-17 21:02:31.000000000 -0600
+++ commands.c	2018-09-18 12:14:03.000000000 -0500
@@ -8,7 +8,7 @@
  */
  
 #include <stdio.h>
-#include <String.h>
+#include <string.h>
 #include "commands.h"
 
 #define DEFAULT_SCALE 1
