  * Test before defining macro _GNU_SOURCE.
  
  * Better use of inline functions and resolved compiler warnings.
  
  * Prevent error messages to grow larger than the maximum size. (issue #82)
  
  * Change return value for siridb_shard_status() from void to int containing
    the number of characters written.
    
  * Updated ct_items() callback function and added the length of the key. 
    The key is no longer terminated so the length must be used.
    
  * Updated the node object for ctree with the key length so we can skip a
    few strlen() calls when doing a lookup.
    
  * We do not save the terminator character on ctree nodes anymore. All get and
    set functions are updated to work without the string termination.
    
  * Removed unused ct_itemsn() function. Since ct_items() shared logic with
    this function we could also clean some additional code.
    
  * Added -Wextra compiler option in all .mk files.