djgpp build instructions

Explicitly mention fil41b.zip as a required djgpp component.
Oddly, some people only pick up part of djgpp, then
complain to us when the Makefile doesn't run as
planned.

sys/msdos/Install.dos

@@ -57,6 +57,9 @@ I.  Dispelling the Myths:
     compilers.  Flex and Bison are included with the DJGPP distribution and 
     are also available on many archive sites. 
 
+    Also be sure to pick up djgpp v2gnu/fil41b.zip to get ls.exe and 
+    touch.exe, since the Makefile uses them by default.
+
 II. To compile your copy of NetHack on a DOS machine:
     (or "just follow these few 'simple' steps outlined below.")
 
@@ -217,6 +220,9 @@ Appendix B - DJGPP Compiler (gcc ported to msdos)
     At the time of this release in April 2002, the URL
 	http://www.delorie.com/djgpp/zip-picker.html/
     had information on how to obtain djgpp and what pieces to get.
+    Be sure to pick up djgpp v2gnu/fil41b.zip to get ls.exe and 
+    touch.exe, since the Makefile uses them by default (or change
+    the Makefile to use alternatives).
 
     Special note for Windows 2000 / Windows XP users: You must have a 
     recent djgpp distribution for the build process, and the generated