Autoload and relative file names

[Lennart Borgman (gmail)]

The function that generates autoload, autoload-generate-file-autoloads,
enters just the file name without extension in the generated autoloads.

This means that the file with the autoloaded functions must be in
load-path. This is not always what is desired.

The function `load' (that I assume does the loading later) can use file
names that are relative to any entry in `load-path'. I think it would be
quite useful to be able to generate the autoload section such that it
uses a file name relative to load-path. This could be done by adding a
new parameter, the directory to make the relative file name against.