ingest: Add macros for ctrl + up/down

I don't think ncurses has macros for these, but the magic numbers I have
in there seem to work. So add macros for those that conform to the rest
of the ncurses KEY_* naming convention.

src/ingest.c

@@ -33,6 +33,13 @@ static int read_cmd_page(const char *home_dir, int idx);
 static void update_cmd_pg_status(void);
 static void inter_command_wait(void);
 
+#ifndef KEY_CUP
+#  define KEY_CUP   (566)
+#endif
+#ifndef KEY_CDOWN
+#  define KEY_CDOWN (525)
+#endif
+
 int
 ingest_start(bytenuts_t *bytenuts)
 {
@@ -801,10 +808,10 @@ handle_functions(int ch)
     case KEY_SEND: /* go to front of log */
         cheerios_gofwd(-1);
         return 1;
-    case 566: /* ctrl + up arrow */
+    case KEY_CUP: /* ctrl + up arrow */
         cheerios_goback(1);
         return 1;
-    case 525: /* ctrl + down arrow */
+    case KEY_CDOWN: /* ctrl + down arrow */
         cheerios_gofwd(1);
         return 1;
     case KEY_RESIZE: