Debian package configure options - repost

[TR <signup@misanthrope.co.uk>]

Simple question - how do I find out what configure options have 
been used in creating a Debian package.

I want to use the Debian squid3 package but need to know what 
configure options were used.

I require the following:-

./configure --enable-auth=”basic” 
-enable-basic-auth-helpers="LDAP" -- enable-ssl 
--enable-auth-on-accel

If the package has not been configured with these options can I 
recompile it.

Thanks,

TR