autom4te ¶The Autoconf suite, including M4sugar, M4sh, and Autotest, in addition
to Autoconf per se, heavily rely on M4. All these different uses
revealed common needs factored into a layer over M4:
autom4te5.
autom4te is a preprocessor that is like m4.
It supports M4 extensions designed for use in tools like Autoconf.