Update autoload definitions for Lisp files in the directories DIRS.
In an interactive call, you must give one argument, the name of a
single directory. In a call from Lisp, you can supply multiple
directories as separate arguments, but this usage is discouraged.
The function does NOT recursively descend into subdirectories of the
directory or directories specified.
In an interactive call, prompt for a default output file for the
autoload definitions, and temporarily bind the variable
`generated-autoload-file' to this value. When called from Lisp,
use the existing value of `generated-autoload-file'. If any Lisp
file binds `generated-autoload-file' as a file-local variable,
write its autoloads into the specified file instead.
(fn &rest DIRS)