(P_SHELL, P_GUN, P_PETROL, P_IRON, P_DUST, P_BAR, P_FOOD, P_OIL)

(P_LCM, P_HCM, P_TLEV, P_RLEV, P_ELEV, P_HLEV, P_URAN): Use -1 instead
of 0 for `no product', shift down product indexes and update
product.config and sector.config accordingly.
(budg, prod, show_sect_capab, produce, produce_sect): Adapt test for
no product.
(ef_elt_byname): Remove the hack to hide pchr[0].
(prod_eff): Oops on no product.

src/lib/common/type.c

@@ -95,9 +95,9 @@ ef_elt_byname(int type, char *name)
 		      offsetof(struct ichrstr, i_name),
 		      sizeof(ichr[0]));
     case EF_PRODUCT:
-	return 1 + stmtch(name, pchr + 1,
-			  offsetof(struct pchrstr, p_sname),
-			  sizeof(pchr[0]));
+	return stmtch(name, pchr,
+		      offsetof(struct pchrstr, p_sname),
+		      sizeof(pchr[0]));
     case EF_TABLE:
 	return stmtch(name, empfile,
 		      offsetof(struct empfile, name),