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).

sys/winnt/Makefile.bcc

@@ -1176,7 +1176,7 @@ $(O)termcap.o: ..\win\tty\termcap.c $(HACK_H) $(INCL)\tcap.h
 $(O)topl.o: ..\win\tty\topl.c $(HACK_H) $(INCL)\tcap.h
 	$(cc) $(CFLAGS) -o$@ ..\win\tty\topl.c
 $(O)wintty.o: ..\win\tty\wintty.c $(HACK_H) $(INCL)\dlb.h \
-		$(INCL)\patchlevel.h $(INCL)\tcap.h
+		$(INCL)\date.h $(INCL)\patchlevel.h $(INCL)\tcap.h
 	$(cc) $(CFLAGS) -o$@ ..\win\tty\wintty.c
 $(O)Window.o: ..\win\X11\Window.c $(INCL)\xwindowp.h $(INCL)\xwindow.h \
 		$(CONFIG_H)

sys/winnt/Makefile.gcc

@@ -1142,7 +1142,7 @@ $(O)termcap.o: ../win/tty/termcap.c $(HACK_H) $(INCL)/tcap.h
 $(O)topl.o: ../win/tty/topl.c $(HACK_H) $(INCL)/tcap.h
 	$(cc) $(CFLAGS) -o$@ ../win/tty/topl.c
 $(O)wintty.o: ../win/tty/wintty.c $(HACK_H) $(INCL)/dlb.h \
-		$(INCL)/patchlevel.h $(INCL)/tcap.h
+		$(INCL)/date.h $(INCL)/patchlevel.h $(INCL)/tcap.h
 	$(cc) $(CFLAGS) -o$@ ../win/tty/wintty.c
 $(O)Window.o: ../win/X11/Window.c $(INCL)/xwindowp.h $(INCL)/xwindow.h \
 		$(CONFIG_H)

sys/winnt/Makefile.msc

@@ -1250,7 +1250,7 @@ $(O)termcap.o: ..\win\tty\termcap.c $(HACK_H) $(INCL)\tcap.h
 $(O)topl.o: ..\win\tty\topl.c $(HACK_H) $(INCL)\tcap.h
 	@$(CC) $(cflagsUtil) -Fo$@ ..\win\tty\topl.c
 $(O)wintty.o: ..\win\tty\wintty.c $(HACK_H) $(INCL)\dlb.h \
-		$(INCL)\patchlevel.h $(INCL)\tcap.h
+		$(INCL)\date.h $(INCL)\patchlevel.h $(INCL)\tcap.h
 	@$(CC) $(cflagsUtil) -Fo$@ ..\win\tty\wintty.c
 $(O)Window.o: ..\win\X11\Window.c $(INCL)\xwindowp.h $(INCL)\xwindow.h \
 		$(CONFIG_H)