(is_prime): Return explicit boolean values.

(hash_get_first): Return NULL to appease Irix5.6's 89.

lib/hash.c

@@ -263,6 +263,7 @@ hash_get_first (const Hash_table *table)
       return bucket->data;
 
   assert (0);
+  return NULL;
 }
 
 /* Return the user data for the entry following ENTRY, where ENTRY has been
@@ -422,7 +423,7 @@ is_prime (unsigned long candidate)
       divisor++;
     }
 
-  return candidate % divisor != 0;
+  return (candidate % divisor ? true : false)
 }
 
 /* Round a given CANDIDATE number up to the nearest prime, and return that