Switch hash tables to longs, as longs guarantee 32 bits.

The default FNV hash requires 32 bits at least.

include/ht.h

@@ -45,7 +45,7 @@ struct ht_s {
    * @param input the data being hashed.
    * @return the data's hash.
    */
-  unsigned int (*hash_func)(void* input);
+  unsigned long (*hash_func)(void* input);
   /**
    * Function to compare two keys.
    * @param given_key the key being used to retrieve data
@@ -76,7 +76,7 @@ typedef struct ht_s ht;
  * @param key the data to hash.
  * @return the produced hashed integer.
  */
-unsigned int ht_default_hash_func(void* key);
+unsigned long ht_default_hash_func(void* key);
 /**
  * The default key comparison function.
  * Assumes both keys are strings and uses strcmp.