(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.

include/nsc.h

@@ -65,6 +65,14 @@ typedef enum {
 } nsc_type;
 typedef char packed_nsc_type;
 
+/* Return nsc_type for a signed integer with the same size as TYPE.  */
+#define NSC_SITYPE(type)				\
+    (sizeof(type) == 1 ? NSC_CHAR			\
+     : sizeof(type) == sizeof(short) ? NSC_SHORT	\
+     : sizeof(type) == sizeof(int) ? NSC_INT		\
+     : sizeof(type) == sizeof(long) ? NSC_LONG		\
+     : 1/0)
+
 /* Value category */
 typedef enum {
     NSC_NOCAT,