We'll also look at some of the macros that these files set or use.
The qconfig.mk include file
Since the common makefiles have a lot of defaults based on the names of various directories, you can simplify your life enormously in the common.mk include file if you choose your directory names to match what the common makefiles want.
The qdepfile.mk include file
The qdepfile.mk include file provides support for dependency list generation to the qcc compiler.