*** System macros ***

Here I will mention some of the important but less obvious macros that are 
defined in defs.h.

THE_VOID - "Room" that master objects are in.

WITH_OBJ - "Room" that objects that are being carried are in. Its not a real
    room , its simply a way of keeping track of them.

SALT - Used for password encryption. Don't ask me why its needed but the
    crypt function requires it for some reason.

STREN_MUL - This multiplied by the objects strength gives the max weight the
    object can carry. Naturally this does not apply to ITEM types.
