So some deranged imagination, came up with the idea of the configure script, which sniffed at your system and set up a Makefile that would work.
Writing configure scripts was hard work, for one thing you needed a ton of different systems to test them on, so copy&paste became the order of the day.
Then some even more deranged imagination, came up with the idea of writing a script for writing configure scripts, and in an amazing and daring attempt at the "all time most deranged" crown, used an obscure and insufferable macro-processor called m4 for the implementation.
Now, as it transpires, writing the specification for the configure producing macros was tedious, so somebody wrote a tool to...