-The file `configure.ac' is the input used by the autoconf program to
-construct the `configure' script. Since Emacs has some configuration
-requirements that autoconf can't meet directly, and for historical
-reasons, `configure.ac' uses an unholy marriage of custom-baked
-configuration code and autoconf macros.
+The file 'configure.ac' is the input used by the autoconf program to
+construct the 'configure' script.