trunk only: preserving context (sys files)

Pat Rankin wrote:
> collect them all into some new struct and
> save that separately rather than jamming more non-option stuff
> into struct flags.

This patch:
- collects all context/tracking related fields from flags
  into a new structure called "context."
It also adds the following to the new structure:
- stethoscope turn support
- victual support
- tin support

sys/vms/Makefile.utl

@@ -159,7 +159,7 @@ $(MAKEDEFS) :	$(MAKEOBJS) $(VMSMAKEOBJS) $(LIBOPT)
       @ $(TOUCH) $(MARKER)
 
 makedefs.obj :	makedefs.c \
-		$(CONFIG_H) $(INC)permonst.h $(INC)objclass.h \
+		$(CONFIG_H) $(IN)context.h $(INC)permonst.h $(INC)objclass.h \
 		$(INC)monsym.h $(INC)artilist.h $(INC)dungeon.h \
 		$(INC)obj.h $(INC)monst.h $(INC)you.h $(INC)flag.h \
 		$(INC)dlb.h $(INC)patchlevel.h $(INC)qtext.h