How to put .desktop launcher in autostart directory using makefile

I want my program to add a .desktop launcher to the ~/.conf/autostart directory. How do I do this?

I already have the following code to put the launcher in the applications directory:

desktopdir = $(datadir)/applications
desktop_in_files = hello_world.desktop.in
dist_desktop_DATA = $(desktop_in_files:.desktop.in=.desktop)

Can you explain what this does exactly and what I have to add to also put it in the autostart folder?

Thanks!