Recommended method for building your own helpers?

[Chris Ross]

  I've written a log_daemon helper, and am writing an external_url helper.  So 
far, I've just been patching the configure and Makefile's in the squid sources, 
then moving my code into the expected place in the tree.  But, I was wondering 
if there is another better/easier method to build helpers _outside_ of the 
squid source tree.  Is there a recommended system to effectively reach into a 
squid source tree from outside to get headers and library code?

  Thanks….

                                       - Chris