All popular clients use GNU Autoconf and GNU Automake, thus come with a configure script. Read the installation instructions after you unpack the sources. Be sure you have the required libraries in order to compile. Doing cd name_of_the_created_directory; ./configure --help; ./configure your_options_here; make; make install > ~/sources_install.log is the right procedure. Also note that for ircII, EPIC, and BitchX you should really edit include/config.h to suit your needs.