Move isqrt into hacklib, other minor fixage

src/spell.c

@@ -42,7 +42,6 @@ STATIC_DCL int NDECL(throwspell);
 STATIC_DCL void NDECL(cast_protection);
 STATIC_DCL void FDECL(spell_backfire, (int));
 STATIC_DCL const char *FDECL(spelltypemnemonic, (int));
-STATIC_DCL int FDECL(isqrt, (int));
 
 /* The roles[] table lists the role-specific values for tuning
  * percent_success().
@@ -1433,29 +1432,6 @@ int *spell_no;
 	return FALSE;
 }
 
-/* Integer square root function without using floating point.
- * This could be replaced by a faster algorithm, but has not been because:
- * + the simple algorithm is easy to read
- * + this algorithm does not require 64-bit support
- * + in current usage, the values passed to isqrt() are not really that
- *   large, so the performance difference is negligible
- * + isqrt() is used in only one place
- * + that one place is not a bottle-neck
- */
-STATIC_OVL int
-isqrt(val)
-int val;
-{
-    int rt = 0;
-    int odd = 1;
-    while(val >= odd) {
-	val = val-odd;
-	odd = odd+2;
-	rt = rt + 1;
-    }
-    return rt;
-}
-
 STATIC_OVL int
 percent_success(spell)
 int spell;