imake was a build automation system used by the X Window System from X11R1 (1987) to X11R6.9 (2005). It was implemented on top of the C preprocessor and make. The first version was written by Todd Brunhoff at Tektronix.
imake generated makefiles from a template, a set of cpp macro functions, and a per-directory input file called an Imakefile. This allowed machine dependencies (such as compiler options, alternate command names, and special make rules) to be kept separate from the descriptions of the various items to be built.
With the release of X.org X11R7.0, it was replaced by GNU autotools. (X11R6.9 and X11R7.0 were the same codebase with a different build system.) imake was then only used by XFree86, which has been dormant since 2009.