Move Amiga port files from outdated/ to sys/amiga/

Move the active Amiga source files back into their proper locations.
Legacy native build files (Makefile.ami, Build.ami, etc.) remain
in outdated/ as they are not used by the cross-compilation build.

sys/amiga/amigst.c

@@ -0,0 +1,49 @@
+/* NetHack 3.6	amigst.c	$NHDT-Date: 1432512794 2015/05/25 00:13:14 $  $NHDT-Branch: master $:$NHDT-Revision: 1.7 $ */
+/*    Copyright (c) Gregg Wonderly, Naperville, IL, 1992, 1993	  */
+/* NetHack may be freely redistributed.  See license for details. */
+
+#include <stdio.h>
+#include <exec/types.h>
+#include <exec/io.h>
+#include <exec/alerts.h>
+#include <exec/devices.h>
+#include <devices/console.h>
+#include <devices/conunit.h>
+#include <graphics/gfxbase.h>
+#include <intuition/intuition.h>
+#include <libraries/dosextens.h>
+#include <ctype.h>
+#undef strcmpi
+#include <string.h>
+#include <errno.h>
+
+#ifdef __SASC
+#include <dos.h> /* for __emit */
+#include <string.h>
+#include <proto/dos.h>
+#include <proto/exec.h>
+#include <proto/graphics.h>
+#include <proto/intuition.h>
+#include <proto/diskfont.h>
+#include <proto/console.h>
+#endif
+
+#include "hack.h"
+#include "winprocs.h"
+#include "winami.h"
+
+#ifdef AZTEC
+#include <functions.h>
+#endif
+
+#ifndef CROSS_TO_AMIGA
+#include "NH:sys/amiga/winami.p"
+#include "NH:sys/amiga/amiwind.p"
+#include "NH:sys/amiga/amidos.p"
+#else
+#include "winami.p"
+#include "amiwind.p"
+#include "amidos.p"
+#endif
+
+/* end amigst.c */