First pass at a hints-based build system to augment (not replace) the existing

build system.

Anyone who wants to do a build from sys/unix and doesn't want to figure this
out just needs to do:
	sh setup.sh hints/unix
instead of:
	sh setup.sh
and then continue on as usual.

New files:
sys/unix/NewInstall.unx - the new directions
sys/unix/hints/* - the hints files.  There will be more later.
sys/unix/mkmkfile.sh - helper for setup.sh

Summary of changes:
see NewInstall.unx for info on the new build system
introduction of various preprocessor symbols to turn options off that
 are defaulted on historically
comment out nethackrc (and similar) entries that still use the old symbol
 syntax.
commenting out of Makefile.* lines that now come from hints/unix
GAMEDIR is replaced with HACKDIR so the Makefiles and the C source agree.
  Note that I have NOT changed the docs and/or Makefiles for be, msdos, os2,
  vms, or winnt.  If port maintainers don't then I will, but I can't test
  those ports.
nethack.sh now handles the font path automatically

include/unixconf.h

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)unixconf.h 3.5	1999/07/02	*/
+/*	SCCS Id: @(#)unixconf.h 3.5	2007/12/12	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -142,8 +142,9 @@
  * variable MAILREADER; otherwise an internal pager will be used.
  * A stat system call is done on the mailbox every MAILCKFREQ moves.
  */
-
+#if !defined(NOMAIL)
 #define MAIL			/* Deliver mail during the game */
+#endif
 
 /* The Andrew Message System does mail a little differently from normal
  * UNIX.  Mail is deposited in the user's own directory in ~/Mailbox