Sectors need space for items, deliveries and distribution thresholds.

To save space, the ancients invented `variables': a collection of
key-value pairs, missing means zero value, space for `enough' keys.
This complicates the code, as assigning to a `variable' can fail for
lack of space.  Over time, `enough' increased, and for quite some time
now `variables' have been *wasting* space.  This changeset replaces
them, except in struct mchrstr, struct lchrstr and struct pchrstr,
where they are read-only, and will be replaced later.  It is only a
first step; further cleanup is required.  To simplify and minimize
this necessarily huge changeset, the new item[] arrays have an unused
slot 0, and the old variable types V_CIVIL, ... are still defined, but
must have the same values as the item types I_CIVIL, ...

src/lib/subs/nstr.c

@@ -218,7 +218,8 @@ decode(natid cnum, long int code, void *addr, int type)
 
     nsc_code = code & NSC_CMASK;
     if (nsc_code == NSC_VAR) {
-	val = getvar(val, addr, type);
+	u_short *item = ef_items(type, addr);
+	val = item ? item[val] : 0;
     } else if (nsc_code == NSC_OFF) {
 	/*
 	 * add offset to value