Fig-1: ZXID Build Process
The build process of ZXID relies heavily on code generation techniques that are not for the faint of heart. Some of these techniques, like xsd2sg.pl were innovated for this project, while others like SWIG and gperf are existing software. Here and there some additional perl(1) and sed(1) scripts are run to fix a thing or two.
Fig-1: ZXID Build Process
Carefully study the Makefile, and this should all start to make sense. Please note that there is no configuration script and GNU Auto-tools (GNU Autohell) are not used. This is because they have been evaluated to be unsuitable to this project (or to author's tastes). If the Makefile does not do what you want, you should first study if you can change necessary variables using localconf.mk, or if that does not work, then just edit the Makefile itself. You can temporarily customize the variables in the Makefile by providing new value on command line, e.g.
make CC=cc # override the default of CC=gcc