Use more enums

We're already using enums, so convert some already existing defines.

include/attrib.h

@@ -7,14 +7,16 @@
 #ifndef ATTRIB_H
 #define ATTRIB_H
 
-#define A_STR 0
-#define A_INT 1
-#define A_WIS 2
-#define A_DEX 3
-#define A_CON 4
-#define A_CHA 5
+enum attrib_types {
+    A_STR = 0,
+    A_INT,
+    A_WIS,
+    A_DEX,
+    A_CON,
+    A_CHA,
 
-#define A_MAX 6 /* used in rn2() selection of attrib */
+    A_MAX /* used in rn2() selection of attrib */
+};
 
 #define ABASE(x) (u.acurr.a[x])
 #define ABON(x) (u.abon.a[x])