(I_NONE, I_CIVIL, I_MILIT, I_SHELL, I_GUN, I_PETROL, I_IRON, I_DUST,

I_BAR, I_FOOD, I_OIL, I_LCM, I_HCM, I_UW, I_RAD, I_MAX): Turn macros
into enumeration constants.
(i_type): New.  Use where appropriate.  No functional changes, except
that I_NONE is now catched properly in a few places.

src/lib/commands/expl.c

@@ -56,7 +56,7 @@ explore(void)
     double weight;
     int mcost, dam;
     int infected;
-    int vtype;
+    i_type vtype;
     int amt_src;
     int amt_dst;
     struct ichrstr *ip;