display version and build info at startup (trunk only)

Tested on the unix port; I've updated as many other ports as I can figure
out but they're not tested.  See window.doc for info on the changed banner
lines.  Also adds the ability to override the generic "Unix" port - used now to get
"MacOSX" into the version line instead of "Unix" (so we don't scare people who don't
know what's going on).

include/global.h

@@ -191,6 +191,9 @@ typedef char nhptext;
 # ifdef MAC
 #  define PORT_ID	"Mac"
 # endif
+# ifdef __APPLE__
+#  define PORT_ID	"MacOSX"
+# endif
 # ifdef MSDOS
 #  ifdef PC9800
 #  define PORT_ID	"PC-9800"
@@ -213,8 +216,11 @@ typedef char nhptext;
 # ifdef TOS
 #  define PORT_ID	"ST"
 # endif
-# ifdef UNIX
-#  define PORT_ID	"Unix"
+	/* Check again in case something more specific has been defined above. */
+# ifndef PORT_ID
+#  ifdef UNIX
+#   define PORT_ID	"Unix"
+#  endif
 # endif
 # ifdef VMS
 #  define PORT_ID	"VMS"

include/patchlevel.h

@@ -17,11 +17,10 @@
 
 #define COPYRIGHT_BANNER_A \
 "NetHack, Copyright 1985-2011"
-
 #define COPYRIGHT_BANNER_B \
 "         By Stichting Mathematisch Centrum and M. Stephenson."
-
-#define COPYRIGHT_BANNER_C \
+	  /* COPYRIGHT_BANNER_C is generated by makedefs into date.h */
+#define COPYRIGHT_BANNER_D \
 "         See license for details."
 
 /*