C preprocessor interface to the make utility

Imake is used to generate Makefiles from a template, a set of cpp macro functions, and a per-directory input file called an Imakefile. The X Window System used imake extensively up through the X11R6.9 release, for both full builds within the source tree and external software. X has since moved to GNU autoconf and automake for its build system in X11R7.0 and later releases, but still maintains imake for building existing external software programs that have not yet converted.