splitting cmd.c, phase 1B

I neglected to use -f with 'git add' and the stub file didn't make
it into the previous commit.

src/insight.c

@@ -0,0 +1,10 @@
+/* NetHack 3.7	insight.c	$NHDT-Date: 1580577249 2020/02/01 17:14:09 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.0 $ */
+/* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
+/* NetHack may be freely redistributed.  See license for details. */
+
+#include "hack.h"
+
+/* temporary, until Makefiles and IDE project files are all updated */
+int insight_dummy = 0;
+
+/*insight.c*/