It is written in Perl, a programming language and commonly used with autoconf, another GNU tool.
See also: autoconf, imake[?]
... area of 16.3 km² (6.3 mi²). 15.3 km² (5.9 mi²) of it is land and 1.0 km² (0.4 mi²) of it is water. The total area is 6.21% water. ...