track the handedness of the hero

Don't make either LEFT_HANDED or RIGHT_HANDED be an advantage
or a disadvantage.

use suggested macros

src/u_init.c

@@ -602,7 +602,7 @@ knows_class(char sym)
 void
 u_init(void)
 {
-    register int i;
+    int i;
     struct u_roleplay tmpuroleplay = u.uroleplay; /* set by rcfile options */
 
     flags.female = flags.initgend;
@@ -903,6 +903,9 @@ u_init(void)
         break;
     }
 
+    /* roughly based on distribution in human population */
+    u.uhandedness = rn2(10) ? RIGHT_HANDED : LEFT_HANDED;
+
     if (discover)
         ini_inv(Wishing);