Autoconf syntax is surprisingly lispy. AC_DEFUN and AC_DEFSUBST seem very similar to lisp's defun and defsubst.
miniblog.
Related Posts
Reflections on the challenges and relevance of Gnu Autotools after the first release in eight years:
Fun post on finding autoconf usage bugs in GTK: https://undeadly.org/cgi?action=article;sid=20170930133438 (always heartening to see experienced devs wrestle with tricky bugs)